A particle dynamic characteristic simulation method and device based on multi-scale fluid-structure coupling

Abstract

The application discloses a kind of based on multiscale fluid-structure coupling particle dynamic characteristic simulation method and device, comprising: generating background grid according to simulated flow field region, local grid is generated according to the position of target particle;Solid domain parameter, fluid domain parameter of current time step are input into fluid-structure coupling model, and target solid domain parameter and target fluid domain parameter are output;Judge whether need to regenerate local grid;If yes, generate new local grid according to target solid domain parameter and obtain the solid domain parameter and fluid domain parameter of new local grid, as the input parameter of next time step;If not, target fluid domain parameter and target solid domain parameter are used as the input parameter of next time step;The process of input and judgment is repeated until the simulation length is reached, and the dynamic characteristics of solid particles are determined according to the target solid domain parameter of each time step.The application can accurately and efficiently carry out multiscale fluid-structure coupling calculation to effectively realize the dynamic characteristic simulation of target particles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid-structure interaction simulation, and in particular to a particle dynamic characteristic simulation method and device based on multi-scale fluid-structure interaction. BACKGROUND

[0002] Fluid-structure interaction (FSI) problems have wide applications in engineering and scientific fields, such as biofluid mechanics, aerospace structure analysis, microfluidic chip design, etc. However, the existing fluid-structure interaction simulation methods mainly face the following problems when dealing with three-dimensional multi-scale problems (multi-scale such as small solid particles and large-scale flow field regions in microfluidic chips, three-dimensional structures such as cylindrical obstacles in flow field regions, etc.):

[0003] (1) Low computational efficiency: Traditional methods usually need to perform global mesh partitioning and solving on the entire calculation domain, and the number of meshes is large, and the equation data to be solved is more, especially when dealing with three-dimensional multi-scale problems, the equation solving is slow, the calculation time is serious, and the simulation period is long; (2) Insufficient interface precision: the physical quantities (such as pressure) at the fluid-structure interface are discontinuous, and the traditional decoupling solving method is easy to introduce numerical error, which leads to distortion of the calculation results at the interface, and even numerical divergence, thereby affecting the accuracy of multi-scale fluid-structure interaction calculation; (3) Limited applicability: Many algorithms are only applicable to two-dimensional or axisymmetric problems, and are difficult to extend to three-dimensional complex geometric structures, which limits their engineering application value.

[0004] At present, there is no effective solution to the above problems. SUMMARY

[0005] The particle dynamic characteristic simulation method and device based on multi-scale fluid-structure interaction provided in the embodiments of the present application solve the problem that the prior art cannot accurately and efficiently perform multi-scale fluid-structure interaction calculation, so as to effectively realize the dynamic characteristic simulation of target particles.

[0006] In a first aspect, the embodiments of the present application provide a particle dynamic characteristic simulation method based on multi-scale fluid-structure interaction, comprising:

[0007] generating a background mesh according to a simulation flow field region where a target particle is located, and generating a local mesh according to a position of the target particle, the background mesh being used to provide a flow field domain boundary for the local mesh, and a difference between a scale of the simulation flow field region and a scale of the target particle being greater than a preset scale threshold;

[0008] inputting a solid domain parameter in the local mesh at a current time step and a fluid domain parameter in the flow field domain boundary into a fluid-structure interaction model, and outputting a target solid domain parameter and a target fluid domain parameter after fluid-structure interaction at the current time step;

[0009] determining whether a local mesh needs to be regenerated according to the target solid domain parameter;

[0010] If yes, a new local mesh is generated according to the target solid domain parameter, and the solid domain parameter and the fluid domain parameter of the new local mesh are obtained as the fluid-structure coupling input parameter of the next time step; if no, the target fluid domain parameter and the target solid domain parameter are taken as the fluid-structure coupling input parameter of the next time step.

[0011] The input and determination process is repeated until the cumulative value of each time step reaches the simulation duration, and the dynamic characteristics of the target particle in the simulated flow field region are determined according to the target solid domain parameter after fluid-structure coupling of each time step, the dynamic characteristics at least including a motion trajectory and a stress distribution.

[0012] In some embodiments, the generating a local mesh according to the position of the target particle comprises:

[0013] generating an initial local mesh according to the position of the target particle;

[0014] identifying a sensitive region and a non-sensitive region in the initial local mesh, the sensitive region being at a curvature of a fluid-structure interface greater than or equal to a preset curvature threshold, or being at a minimum distance of the fluid-structure interface to a calculation domain boundary being a preset distance threshold;

[0015] subdividing a grid cell in the sensitive region, merging adjacent grid cells in the non-sensitive region, and performing quality optimization processing on the grid cells in the sensitive region and the non-sensitive region to obtain the local mesh.

[0016] In some embodiments, the fluid-structure coupling model is composed of the following equations:

[0017]

[0018] wherein u is a velocity field of a fluid domain and a solid domain; w t is a motion velocity of the target particle; P s is a pressure field of the solid domain; P f is a pressure field of the fluid domain; Re is a Reynolds number; D is a symmetric gradient tensor of the velocity field; E is a Young's modulus of the target particle; B is a left Cauchy-Green tensor for describing deformation of the target particle; I is a unit matrix; T is a simulation duration; is the entire calculation domain composed of the solid domain and the fluid domain; is the solid domain; is the fluid domain; is used for describing a spatial variation of a physical quantity; is used for describing a diffusion process of a physical quantity.

[0019] In some embodiments, the fluid-structure coupling model processes the input solid domain parameters in the current time step local mesh, the fluid domain parameters inside the flow field domain boundary in the following manner:

[0020] Based on the solid domain parameters, the fluid domain parameters of the current time step, determine the intermediate parameters of the solid domain, the intermediate parameters of the fluid domain between the current time step and the next time step in a scaled time step, the scaled time step being determined by adjusting the time step by adjusting the parameters;

[0021] Linearly combine the intermediate parameters of the solid domain, the intermediate parameters of the fluid domain with the solid domain parameters, the fluid domain parameters of the current time step to obtain the corrected solid domain parameters, the corrected fluid domain parameters;

[0022] Based on the corrected solid domain parameters, the corrected fluid domain parameters, determine and output the target solid domain parameters and the target fluid domain parameters after fluid-structure coupling of the current time step in a scaled time step.

[0023] In some embodiments, the solid domain parameters include at least one of the following: velocity field of the solid domain, target particle movement velocity, pressure field of the solid domain, Young's modulus of the target particle, left Cauchy Green tensor; the fluid domain parameters include at least one of the following: velocity field of the fluid domain, pressure field of the fluid domain, fluid density, dynamic viscosity.

[0024] In some embodiments, the determining whether the local mesh needs to be regenerated according to the target solid domain parameters comprises:

[0025] Determining the target position of the target particle according to the target movement velocity of the target particle;

[0026] Determining the difference between the target position of the target particle and the initial position of the target particle as the displacement amplitude of the target particle, and determining the difference between the target left Cauchy Green tensor of the target particle and the left Cauchy Green tensor of the target particle as the deformation degree of the target particle;

[0027] Determining whether the displacement amplitude and the deformation degree exceed the corresponding preset threshold value;

[0028] If yes, it is determined that the local mesh needs to be regenerated; if no, it is determined that the local mesh does not need to be regenerated.

[0029] In some embodiments, the generating a new local mesh and obtaining the solid domain parameters, the fluid domain parameters of the new local mesh comprises:

[0030] Generating a new local mesh according to the new position of the target particle, and determining the overlapping area and the non-overlapping area of the new local mesh and the old local mesh;

[0031] interpolating the target solid domain parameters and the target fluid domain parameters to the overlap region, interpolating a background flow field in a background mesh to the non-overlap region, and taking the interpolated parameters as solid domain parameters and fluid domain parameters of a new local mesh.

[0032] In some embodiments, the determining of the dynamic characteristics of the target particle in the simulation flow field region according to the target solid domain parameters after the fluid-solid coupling at each time step comprises:

[0033] superimposing the target motion velocities of the target particle at each time step to determine a motion trajectory of the target particle in the simulation flow field region of the target microfluidic chip.

[0034] determining a stress distribution of the target particle in the simulation flow field region of the target microfluidic chip according to the target left Cauchy Green tensor at each time step.

[0035] In a second aspect, the embodiments of the present specification also provide a particle dynamic characteristic simulation device based on multi-scale fluid-solid coupling, comprising:

[0036] a background and local mesh generation module configured to generate a background mesh according to a simulation flow field region in which a target particle is located, and generate a local mesh according to a position of the target particle, the background mesh being configured to provide a flow field region boundary for the local mesh, and the simulation flow field region being different from a scale of the target particle by more than a preset scale threshold;

[0037] a fluid-solid coupling simulation module configured to input solid domain parameters in the local mesh at a current time step and fluid domain parameters in the flow field region boundary to a fluid-solid coupling model, and output target fluid domain parameters and target solid domain parameters after fluid-solid coupling at the current time step;

[0038] a judgment module configured to judge whether the local mesh needs to be regenerated according to the target solid domain parameters;

[0039] an input parameter determination module configured to, if yes, generate a new local mesh according to the target solid domain parameters, and take solid domain parameters and fluid domain parameters of the new local mesh as input parameters for fluid-solid coupling at a next time step; and if no, take the target fluid domain parameters and the target solid domain parameters as the input parameters for fluid-solid coupling at the next time step;

[0040] a dynamic characteristic determination module configured to repeat the process of inputting and judging until a cumulative value of each time step reaches a simulation time length, and determine dynamic characteristics of the target particle in the simulation flow field region according to the target solid domain parameters after the fluid-solid coupling at each time step, the dynamic characteristics at least including a motion trajectory and a stress distribution.

[0041] In a third aspect, the embodiments of the present specification also provide a computer-readable storage medium having stored thereon computer programs / instructions, which, when executed by a processor, implement the steps of the above-mentioned particle dynamic characteristic simulation method based on multi-scale fluid-structure coupling.

[0042] The embodiments of the present specification provide a particle dynamic characteristic simulation method and device based on multi-scale fluid-structure coupling. First, a background grid is generated according to a simulation flow field region where a target particle is located, and a local grid is generated according to a position of the target particle. The background grid is used to provide a flow field domain boundary for the local grid. The simulation flow field region has a scale difference greater than a preset scale threshold from the target particle. Then, a solid domain parameter in the current time step local grid and a fluid domain parameter in the flow field domain boundary are input into a fluid-structure coupling model, and target solid domain parameters and target fluid domain parameters after fluid-structure coupling in the current time step are output. Whether the local grid needs to be regenerated is judged according to the target solid domain parameters in the current time step. If yes, a new local grid is generated according to the target solid domain parameters in the current time step, and the solid domain parameters and the fluid domain parameters of the new local grid are obtained as the fluid-structure coupling input parameters in the next time step; if no, the target solid domain parameters and the target fluid domain parameters after fluid-structure coupling in the current time step are taken as the fluid-structure coupling input parameters in the next time step. Finally, the input and judgment process is repeated until the cumulative value of each time step reaches the simulation duration. The dynamic characteristics of the target particle in the simulation flow field region are determined according to the target solid domain parameters in each time step. The dynamic characteristics include at least a motion trajectory and a stress distribution. In the embodiments of the present specification, the background grid and the local grid are generated. The background grid provides a local flow field domain boundary for the local grid. The fluid-structure coupling simulation is performed only on the local grid by using the solid domain parameters in the local grid and the fluid domain parameters in the local flow field domain boundary, thereby avoiding the problems of low calculation efficiency and long simulation period caused by global grid division and solving. The calculation efficiency of fluid-structure coupling in a three-dimensional multi-scale fluid-structure coupling scene can be improved, and the calculation resources can be greatly saved. The fluid-structure coupling model can avoid the problem of discontinuity of physical quantities (such as pressure) at the fluid-structure interface, thereby improving the accuracy and efficiency of fluid-structure coupling calculation. By judging whether the local grid needs to be regenerated, the fluid-structure coupling simulation in the next time step can be accurately and efficiently performed in a complex three-dimensional multi-scale fluid-structure coupling scene. Finally, the motion trajectory and the stress distribution of the target particle in the simulation flow field region are determined according to the target solid domain parameters in each time step, which can provide reliable data support for engineering problems in the fields of microfluidic chip design and biofluid mechanics. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to make the technical solutions in the specification embodiments or prior art clearer, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the specification, and other drawings can be obtained by those skilled in the art without creative labor on the premise of the drawings.

[0044] Figure 1 is a flowchart of a particle dynamic characteristic simulation method based on multi-scale fluid-solid coupling provided by the embodiments of the specification;

[0045] Figure 2 is a local grid schematic diagram provided by the embodiments of the specification;

[0046] Figure 3 is a motion trajectory simulation schematic diagram of a target particle in a microfluidic chip provided by the embodiments of the specification;

[0047] Figure 4 is an update schematic diagram of a local grid provided by the embodiments of the specification;

[0048] Figure 5 is a structural composition schematic diagram of a particle dynamic characteristic simulation device based on multi-scale fluid-solid coupling provided by the embodiments of the specification;

[0049] Figure 6 is a structural composition schematic diagram of an electronic device provided by the embodiments of the specification. DETAILED DESCRIPTION

[0050] In order to make those skilled in the art better understand the technical solutions in the specification, the technical solutions in the embodiments of the specification will be clearly and completely described below in combination with the drawings in the embodiments of the specification. Obviously, the described embodiments are only some of the embodiments of the specification, not all the embodiments. Based on the embodiments in the specification, all other embodiments obtained by those skilled in the art without creative labor should be within the protection scope of the specification.

[0051] As described above, the fluid-solid coupling (FSI) problem has a wide range of applications in engineering and scientific fields, such as biofluid mechanics, aerospace structure analysis, microfluidic chip design, etc. However, the existing fluid-solid coupling simulation method mainly faces the following problems when dealing with three-dimensional multi-scale problems (multi-scale such as small solid particles and large-scale flow field region in microfluidic chip, three-dimensional structure such as circular column-shaped obstacles in flow field region, etc.):

[0052] (1) Low computational efficiency: due to the large number of equations to be solved and the huge number of grids, especially when dealing with three-dimensional multi-scale structures (such as coupling of small solid structures and large-scale fluid domains), the equation solving is slow, and the simulation period is long; (2) Difficulty in precision control: the traditional method tends to decouple the control equation and solve it separately, which will easily cause the numerical result to be not high enough in precision, and play a very limited role in engineering applications; (3) Difficulty in matching interface pressure: the pressure at the fluid-structure interface is discontinuous, which makes many numerical algorithms generally have error problems when calculating. Especially in the case of large hardness (Young's modulus) of the solid, the numerical oscillation and discontinuity of physical quantities at the interface will be more serious, resulting in distortion of the calculation results, and even numerical divergence; (4) Some algorithms are only applicable to two-dimensional or axisymmetric problems, which makes it difficult to extend to real three-dimensional complex geometric structures, greatly limiting the engineering application prospect of the algorithm.

[0053] To solve the above problems, the embodiments of the present specification provide a particle dynamic characteristic simulation method and device based on multi-scale fluid-structure coupling. First, a background grid is generated according to a simulation flow field region where a target particle is located, and a local grid is generated according to the position of the target particle. The background grid is used to provide a flow field domain boundary for the local grid. The simulation flow field region and the size difference of the target particle are greater than a preset size threshold. Then, the solid domain parameters in the local grid at the current time step and the fluid domain parameters in the flow field domain boundary are input into a fluid-structure coupling model, and the target solid domain parameters and the target fluid domain parameters after fluid-structure coupling at the current time step are output. Then, it is judged whether the local grid needs to be regenerated according to the target solid domain parameters at the current time step. If yes, a new local grid is generated according to the target solid domain parameters at the current time step, and the solid domain parameters and the fluid domain parameters of the new local grid are obtained as the fluid-structure coupling input parameters at the next time step; if no, the target fluid domain parameters and the target solid domain parameters after fluid-structure coupling at the current time step are taken as the fluid-structure coupling input parameters at the next time step. Finally, the input and judgment process is repeated until the cumulative value of each time step reaches the simulation time length, and the dynamic characteristics of the target particle in the simulation flow field region are determined according to the target solid domain parameters at each time step. The dynamic characteristics at least include the motion trajectory and the stress distribution.

[0054] The application can significantly reduce the calculation amount and improve the calculation efficiency by generating a local grid and a background grid and performing fluid-solid coupling simulation on the local grid. By setting the scale difference between the simulation flow field region and the target particle to be greater than a preset scale threshold, and then outputting the target solid domain parameters and the target fluid domain parameters after fluid-solid coupling through the fluid-solid coupling model, the calculation efficiency of multi-scale fluid-solid coupling can be improved, and the problems of low multi-scale calculation efficiency, poor fluid-solid interface precision and difficult interface pressure matching can be solved. By judging whether the local grid needs to be regenerated, the fluid-solid coupling input parameters of the next time step can be accurately determined, thereby ensuring the fluid-solid coupling precision of the next time step, and finally the motion trajectory and stress distribution simulation of the target particle in the simulation flow field region can be effectively realized. The application is suitable for three-dimensional multi-scale fluid-solid coupling calculation and has high engineering application prospect.

[0055] It should be noted that the "particle" in the application can include rigid body particles, elastic body particles, viscoelastic particles and other solid particles with mechanical characteristics. Both types of particles can be used for simulation calculation. The "dynamic characteristics" can refer to all physical quantities that change over time in the model, which can include the change characteristics of the velocity field of fluid and solid over time, the change characteristics of the position of solid particles over time, the change characteristics of the internal stress of solid particles over time, the change characteristics of the force on solid particles over time, etc. The "fluid-solid coupling" can refer to the process of combining the dynamic equations describing the flow of fluid and the dynamic equations describing the motion and force of solid in a mathematical modeling manner to solve together, which can accurately simulate the interaction between the solid and fluid moving in the fluid and the dynamic evolution characteristics.

[0056] It can be understood that the above method provided by the embodiments of the present application can be applied to an electronic device, which can refer to an electronic device with data calculation, processing and storage capabilities. The electronic device can be a terminal such as a PC (Personal Computer), a tablet computer, a smart phone, a wearable device, a smart robot, etc.; or a server. The server can be a physical server, a server cluster or a distributed system composed of multiple physical servers, or a cloud server providing cloud computing services.

[0057] Referring to Figure 1 The embodiments of the present application provide a particle dynamic characteristic simulation method based on multi-scale fluid-solid coupling. In specific implementation, the method can include the following contents:

[0058] S101: generating a background grid according to a simulation flow field region where a target particle is located, and generating a local grid according to the position of the target particle, the background grid being used to provide a flow field domain boundary for the local grid, and the scale difference between the simulation flow field region and the target particle being greater than a preset scale threshold.

[0059] Specifically, the target particle can be a solid particle, the simulation flow field region can be the entire flow field region in the microfluidic chip, and the entire flow field region can be taken as the simulation flow field region. The background mesh can be an overall large background mesh generated in the entire simulation flow field region, and a corresponding finite element space can be established on the background mesh. The local mesh can be a body-fitted local mesh or a local body-fitted mesh generated near the position of the target particle, and variables (such as left Cauchy-Green tensor) used to describe the velocity field, the pressure field and the solid structure state can be defined on the local mesh. The scale of the target particle is far smaller than the scale of the simulation flow field region, that is, the difference between the scale of the simulation flow field region and the scale of the target particle is greater than a preset scale threshold. By generating the background mesh and the local mesh, the background mesh provides a local flow field region boundary for the local mesh, based on which multi-scale fluid-structure coupling calculation can be accurately and efficiently performed, the complexity of three-dimensional multi-scale fluid-structure coupling calculation is significantly reduced, the physical precision of the local region of the target particle is maintained, and the dynamic characteristic simulation of the target particle in the simulation flow field region is effectively realized, thereby solving the problem that the prior art cannot accurately and efficiently perform multi-scale fluid-structure coupling or three-dimensional multi-scale fluid-structure coupling calculation.

[0060] In some embodiments, before S101, in specific implementation, the method can further include:

[0061] obtaining an inlet velocity field and an inlet pressure field of the target particle in the simulation flow field region, inputting the inlet velocity field and the inlet pressure field into a background flow field prediction model, and outputting a background flow field in the background mesh, wherein the background flow field includes a background velocity field and a background pressure field;

[0062] Correspondingly, the background mesh in S101 is used to provide a flow field region boundary for the local mesh, and in specific implementation, can include:

[0063] interpolating the background velocity field to the boundary of the local mesh, and taking the interpolated boundary as the flow field region boundary of the local mesh.

[0064] Specifically, a background mesh covering the whole flow field region (such as a microfluidic chip channel) can be generated in the whole simulated flow field region, which can be a global coarse mesh, usually a non-body-fitted structured or unstructured mesh (such as hexahedral or tetrahedral elements), with a relatively low resolution to save computing resources. Then, a corresponding finite element space is established on the background mesh, and by giving the inlet velocity field, the outlet pressure field and the no-slip boundary condition on the rest of the boundary, a simple Navier-Stokes equation without solid coupling term is solved by using P2-P1 finite element method. Under the condition of giving a suitable time step, after a sufficient time, a stable background pure flow field is finally obtained, thereby providing basic boundary information for subsequent local calculation. Specifically, the above-mentioned background flow field prediction model can be constructed based on the Navier-Stokes equation ignoring the solid coupling term, and the inlet velocity field and the outlet pressure field of the target particle in the simulated flow field region are input into the background flow field prediction model. The background flow field in the background mesh is output, and the background velocity field in the background flow field is interpolated to the boundary of the local mesh to obtain the flow field boundary of the local mesh. The expression of the Navier-Stokes equation ignoring the solid coupling term can be as follows:

[0065] (1)

[0066] Where u is the velocity field of the fluid domain; P is the pressure field of the fluid domain; and Re is the Reynolds number. f f It should be noted that if the background flow field is significantly affected by the motion of the solid (such as the blocking effect), the background flow field can be solved periodically (such as updated once every time step), and the flow field boundary of the local mesh is updated periodically accordingly.

[0067] It should be noted that if the background flow field is significantly affected by the motion of the solid (such as the blocking effect), the background flow field can be solved periodically (such as updated once every time step), and the flow field boundary of the local mesh is updated periodically accordingly.

[0068] In some embodiments, the local mesh generated according to the position of the target particle in S101 can include the following steps in specific implementation:

[0069] generating an initial local mesh according to the position of the target particle;

[0070] identifying sensitive areas and non-sensitive areas in the initial local mesh, wherein the sensitive areas have a curvature greater than or equal to a preset curvature threshold at the fluid-solid interface, or have a minimum distance from the calculation domain boundary that is greater than or equal to a preset distance threshold;

[0071] subdividing the grid elements in the sensitive areas and merging the adjacent grid elements in the non-sensitive areas, and then performing quality optimization processing on the grid elements in the sensitive areas and the non-sensitive areas to obtain the local mesh.

[0072] ​Specifically, an initial local grid (a second-order body-fitted grid) can be generated in the vicinity of the target particle (or a local small window of the target particle) by using a disclosed grid generation software, to ensure that the initial local grid has high geometric shape preservation at the fluid-structure interface and can accurately depict complex features such as interface bending, convexity and concavity. The type of the initial local grid generated in this process can be a second-order tetrahedron, which supports high-order solving under the finite element framework. Then, sensitive areas and non-sensitive areas in the initial local grid can be identified (only the sensitive areas need to be identified, and the areas in the initial local grid other than the sensitive areas are regarded as non-sensitive areas). The identification method is as follows: determining the areas where the curvature of the fluid-structure interface is greater than a preset curvature threshold, or determining the areas where the minimum distance of the fluid-structure interface to the boundary of the calculation domain is less than a preset distance threshold, or determining the areas where there is a sharp change in slope or the solid boundary is very close to the boundary of the calculation domain, or determining the areas where the velocity gradient, pressure gradient, and stress concentration exist. These areas are regarded as sensitive areas. The above-mentioned determination method of the sensitive areas can be selected according to actual conditions, and of course, there can be other determination methods, which are not limited in the present specification. Then, the sensitive areas and the non-sensitive areas can be marked in the local grid. In the sensitive areas, the original grid elements can be automatically subdivided to increase the number of grid elements, and in the non-sensitive areas, a reconstruction algorithm can be used to merge adjacent grid elements to reduce the number of grid elements. Finally, the grid elements in the sensitive areas and the non-sensitive areas can be subjected to quality optimization processing, such as topology consistency check and quality optimization (such as minimum element angle, Jacobian positive value, etc.), to improve the grid quality by Laplacian smoothing algorithm, to ensure the stability of numerical solving, and to finally obtain a high-quality local grid that meets the geometric fitting accuracy requirement and has good numerical stability. The dark area in the figure can be referred to as the fluid area (fluid domain) of the local grid, and the light area can be referred to as the solid area (solid domain) of the local grid. Figure 2 Figure 2

[0073] Through the above process, the number of degrees of freedom required for simulation can be effectively controlled while ensuring the grid accuracy of key physical areas, thereby reducing the memory and computing burden, and providing an efficient and feasible grid generation basis for large-scale three-dimensional multi-scale flow coupling simulation.

[0074] ​​In some embodiments, the local small window of the target particle can be adaptively positioned and adjusted according to the changes of physical quantities such as velocity, pressure, stress, and particle spatial position. During the time advancement process, only the nodes and elements within the window are executed to perform the update step, and the non-critical area (non-overlapping area) remains the state of the previous time step. Such a local update mechanism significantly reduces the calculation scale of each time step, especially in large-scale three-dimensional structural scenarios, which can effectively compress the calculation amount and accelerate the convergence. Compared with the traditional global coupling method, the local update algorithm described in the present application not only ensures the overall solving accuracy, but also makes it possible for the simulation program to run in parallel on a single node with a low number of cores (10-20 cores), greatly saving the computing resources. At the same time, it can also reduce the total simulation time by more than 98%, and is especially suitable for multi-scale fluid-structure interaction problems with strong local variation characteristics.

[0075] S102: input the solid domain parameters in the local grid at the current time step and the fluid domain parameters within the flow field domain boundary into the fluid-structure coupling model, and output the target solid domain parameters and the target fluid domain parameters after fluid-structure coupling at the current time step.

[0076] Specifically, the solid domain parameters in the local grid at the current time step and the fluid domain parameters within the flow field domain boundary can be determined by assigning initial values to the function spaces of the velocity field, pressure field, displacement field, and deformation field established on the local grid. The fluid-structure coupling model can be composed of multiple equations and is a dynamic grid three-dimensional fast fluid-structure coupling calculation model. At the current time step, the solid domain parameters and the fluid domain parameters can be input into the fluid-structure coupling model to output the velocity field, pressure field, left Cauchy-Green tensor, dynamic grid, or target particle motion velocity after fluid-structure coupling or three-dimensional coupling at the current time step, wherein the target particle motion velocity will cause the local grid position to move, thereby affecting the input parameters (or fluid-structure coupling input parameters) input into the fluid-structure coupling model at the next time step. Through the dynamic grid, multi-scale fluid-structure coupling calculation at multiple time steps can be realized, and finally data basis for dynamic characteristic simulation of the target particle in the simulated flow field region is provided.

[0077] In some embodiments, the fluid-structure coupling model in S102 can be composed of the following equations:

[0078] (2)

[0079] where u is the velocity field of the fluid domain and the solid domain; w t is the motion velocity of the target particle; P s is the pressure field of the solid domain; P fis the pressure field of the fluid domain; Re is the Reynolds number; D is the symmetric gradient tensor of the velocity field; E is the Young's modulus of the target particle; B is the left Cauchy-Green tensor for describing the deformation of the target particle; I is the unit matrix; T is the simulation time length; is the entire calculation domain constituted by the solid domain and the fluid domain; is the solid domain; is the fluid domain; is used for describing the spatial variation of a physical quantity; is used for describing the diffusion process of a physical quantity.

[0080] wherein, (3).

[0081] Specifically, the equations from top to bottom in the above equation (2) can be called, in sequence, a momentum equation (describing fluid-solid coupling), a continuity equation (describing incompressible fluid), a solid deformation equation (describing the evolution of the left Cauchy-Green tensor), and the last two equations are collectively referred to as mesh motion equations. Equation (2) constitutes the above fluid-solid coupling model (fluid-solid coupling equation set). By constructing the fluid-solid coupling model through the above equation set, the following technical effects can be achieved:

[0082] As can be seen from equation (2), in order to adapt to the discontinuity of the pressure at the interface, the present application adopts a spatial splitting method to split the original pressure continuous function space into a solid part P s and a liquid part P f two spaces. The two overlap at the fluid-solid interface, but since they belong to different function spaces, they do not affect each other and each satisfies the equation in the region, so that the problem of fluid-solid coupling calculation distortion caused by pressure discontinuity is avoided.

[0083] And, the equation (2) is coupled, and in the case of complete initial conditions and boundary conditions, a fully coupled discrete format can be constructed, and a weak form of finite element, and finally a large matrix containing all the information in the model can be assembled. No matter what condition, only one solution of the large matrix is needed to get all the physical quantity outputs in a unit time step, that is, all equations can be solved by one-step calculation, which has high calculation precision and efficiency.

[0084] In the fluid-solid model, the motion velocity w t of the target particle can be directly solved. The target particle can be moved according to the motion velocity w t of the target particle, and then the position of the target particle moved in this time can be directly obtained, which affects the operation of the next time step. Through this method, the local mesh at different times can be quickly generated and the detailed tracking of the motion trajectory of the target particle can be realized.

[0085] In some embodiments, the fluid-structure coupling model in S102 above processes the inputted solid domain parameters in the current time step local grid, fluid domain parameters inside the flow field domain boundary in the following way:

[0086] Based on the solid domain parameters and the fluid domain parameters of the current time step, intermediate parameters of the solid domain and the fluid domain between the current time step and the next time step are determined in a scaled time step length, which is determined by adjusting the time step length by adjusting parameters;

[0087] The intermediate parameters of the solid domain and the fluid domain are linearly combined with the solid domain parameters and the fluid domain parameters of the current time step to obtain corrected solid domain parameters and corrected fluid domain parameters;

[0088] Based on the corrected solid domain parameters and the corrected fluid domain parameters, target solid domain parameters and target fluid domain parameters after fluid-structure coupling of the current time step are determined and outputted in a scaled time step length.

[0089] In some embodiments, the solid domain parameters can include at least one of the following: velocity field of the solid domain, movement velocity of target particles, pressure field of the solid domain, Young's modulus of target particles, left Cauchy-Green tensor; the fluid domain parameters can include at least one of the following: velocity field of the fluid domain, pressure field of the fluid domain, fluid density, dynamic viscosity.

[0090] Specifically, the fluid-structure coupling model can adopt a time-discretization method in the solving process of each time step (the process of processing the input parameters of each time step), i.e., the fluid-structure coupling model can be a time-discretization optimized model. This method effectively improves the time accuracy by introducing an intermediate prediction step at each time step, and can more efficiently determine the input parameters of the next time step, and has better time evolution performance under the same error tolerance compared with the traditional first-order method. The specific steps are as follows:

[0091] In each time step t n →t n+1 , (i.e., between the current time step t n and the next time step t n+1 ), first, a predictive calculation is performed with the input parameters of the current time step (such as the velocity field of the solid domain, the pressure field of the solid domain, the velocity field of the fluid domain, the pressure field of the fluid domain, etc.) as the initial value to obtain the physical variables of the intermediate state t (1) (referred to as the predicted solution). Then, based on the intermediate state, a correction step is performed again to obtain a higher-precision t n+1 time solution.

[0092] Specifically, the fluid-structure coupling model processes the solid domain parameters in the current time step local grid, the fluid domain parameters inside the flow field domain boundary in the following specific process:

[0093] Firstly, the intermediate parameters of the solid domain and the intermediate parameters of the fluid domain between the current time step and the next time step can be determined based on the solid domain parameters and the fluid domain parameters of the current time step, in a scaled time step, according to the following formula (4):

[0094] (4)

[0095] wherein, U (1) are the intermediate parameters of the solid domain and the intermediate parameters of the fluid domain between the current time step and the next time step (which can be collectively referred to as intermediate parameters); U n are the solid domain parameters and the fluid domain parameters of the current time step (which can be collectively referred to as input parameters); is the scaled time step; is the adjustment parameter, ; is the time step; F represents the solving process of the equation set corresponding to the fluid-structure coupling model (which can represent the solver of the fluid-structure coupling model).

[0096] Secondly, the intermediate parameters of the solid domain and the intermediate parameters of the fluid domain can be linearly combined with the solid domain parameters and the fluid domain parameters of the current time step to obtain the corrected solid domain parameters and the corrected fluid domain parameters according to the following formula (5):

[0097] (5)

[0098] wherein, U * are the corrected solid domain parameters and the corrected fluid domain parameters (which can be collectively referred to as corrected parameters); U n are the solid domain parameters and the fluid domain parameters of the current time step; U (1) are the intermediate parameters of the solid domain and the intermediate parameters of the fluid domain between the current time step and the next time step.

[0099] Finally, the target solid domain parameters and the target fluid domain parameters after fluid-structure coupling of the current time step can be determined and output based on the corrected solid domain parameters and the corrected fluid domain parameters, in a scaled time step, according to the following formula (10):

[0100] (6)

[0101] wherein, U n+1 are the target solid domain parameters and the target fluid domain parameters after fluid-structure coupling of the current time step (which can be collectively referred to as output parameters); U * are the corrected solid domain parameters and the corrected fluid domain parameters; is the scaled time step; F represents the solving process of the equation set corresponding to the fluid-structure coupling model.

[0102] wherein, Un may include: the velocity field of the fluid domain and the solid domain at the current time step, the fluid domain pressure field, the solid domain pressure field, the solid deformation tensor (i.e. the left Cauchy-Green tensor), the target particle motion velocity, etc. n+1 may include: the target velocity field of the fluid domain and the solid domain after the fluid-structure coupling at the current time step, the target fluid domain pressure field, the target solid domain pressure field, the target solid deformation tensor (i.e. the left Cauchy-Green tensor), the target motion velocity of the target particle, etc., which can be used as the input parameters of the fluid-structure coupling at the next time step.

[0103] The present application optimizes the time discretization of the fluid-structure coupling model, significantly reduces the total number of cycles, and saves the overall calculation time by appropriately increasing the time step size while keeping the error magnitude unchanged. Numerical experiments show that, after using the above-mentioned time discretization optimization strategy, the calculation efficiency can be improved by 50% to 80% while keeping the stability of the solid-liquid interface coupling and the solution accuracy unchanged. In addition, due to the introduction of curved boundaries and non-orthogonal grid structures by local body-fitted grids, the use of lower-order time discretization formats can easily lead to stability deterioration. After using the above-mentioned time discretization optimization strategy, a more stable and smooth interface force propagation path can be provided, improving the consistency of physical quantities at the fluid-structure interface. By optimizing the time discretization of the fluid-structure coupling equation set from first order to second order, a larger time step size is allowed while keeping the same numerical error level, thereby reducing the total number of time steps and significantly improving the calculation efficiency. The above method is suitable for three-dimensional simulation of multi-scale fluid-structure coupling problems.

[0104] In some embodiments, the above-mentioned fluid density and dynamic viscosity can be used to calculate the Reynolds number.

[0105] S103: Determine whether local grids need to be regenerated according to the target solid domain parameters.

[0106] Specifically, by determining whether local grids need to be regenerated, the input parameters for the fluid-structure coupling at the next time step can be accurately determined, thereby ensuring the calculation accuracy of the multi-scale fluid-structure coupling at the next time step.

[0107] In some embodiments, the determination of whether local grids need to be regenerated according to the target solid domain parameters in S103 can include:

[0108] According to the target motion velocity of the target particle, determine the target position of the target particle;

[0109] Determine the difference between the target position of the target particle and the initial position of the target particle as the displacement amplitude of the target particle, and determine the difference between the target left Cauchy-Green tensor of the target particle and the left Cauchy-Green tensor of the target particle as the deformation degree of the target particle.

[0110] determine whether the displacement amplitude and the deformation degree exceed corresponding preset thresholds;

[0111] If yes, it is determined that the local grid needs to be regenerated; if no, it is determined that the local grid does not need to be regenerated.

[0112] Specifically, after obtaining the target motion speed of the target particle, the moving position (target position) of the target particle can be determined according to the following formula:

[0113] (7)

[0114] wherein x n+1 is the target position of the target particle; x n may be the initial position of the target particle; w t n+1 is the target motion speed of the target particle; is a time step.

[0115] Then, the difference between the target position of the target particle and the initial position of the target particle can be determined as the displacement amplitude of the target particle at the current time step, and the difference between the target left Cauchy-Green tensor of the target particle and the initial left Cauchy-Green tensor of the target particle can be determined as the deformation degree of the target particle at the current time step. If the displacement amplitude and the deformation degree at the current time step are greater than or equal to corresponding preset thresholds, it can be determined that the local grid in which the target particle is located is degenerated or the displacement of the target particle is too large, and the local grid needs to be regenerated. If the displacement amplitude and the deformation degree are less than the corresponding preset thresholds, the calculation of the next time step is entered.

[0116] By checking the deformation degree and the displacement amplitude, the problem of numerical calculation divergence or non-convergence caused by excessive distortion of the grid can be avoided, thereby ensuring the stability of the simulation process. If the preset threshold is not exceeded, the grid does not need to be reconstructed, and the next time step is directly entered, thereby reducing unnecessary calculation overhead and improving overall efficiency. If the preset threshold is exceeded, i.e., the solid particle moves too much or the grid quality deteriorates seriously, reconstructing the local body-fitted grid can accurately capture the new geometric shape and ensure the geometric fidelity of the simulation.

[0117] S104: If yes, generating a new local grid according to the target solid domain parameters of the current time step and obtaining the solid domain parameters and the fluid domain parameters of the new local grid as the fluid-solid coupling input parameters of the next time step; if no, taking the target fluid domain parameters and the target solid domain parameters after fluid-solid coupling of the current time step as the fluid-solid coupling input parameters of the next time step.

[0118] Specifically, if the displacement amplitude and the deformation degree at the current time step are greater than or equal to the corresponding preset threshold, the new local grid can be generated according to the target solid domain parameter at the current time step, and the solid domain parameter and the fluid domain parameter of the new local grid are obtained, wherein part of the solid domain parameter and the fluid domain parameter in the solid domain parameter and the fluid domain parameter of the new local grid come from the target solid domain parameter and the target fluid domain parameter output at the last time step, and another part comes from the solid domain parameter and the fluid domain parameter defined by the background grid. If the displacement amplitude and the deformation degree at the current time step are less than the corresponding preset threshold, the target solid domain parameter and the target fluid domain parameter output at the last step can be directly used as the fluid-solid coupling input parameter at the next time step.

[0119] In some embodiments, the generation of the new local grid and the obtaining of the solid domain parameter and the fluid domain parameter of the new local grid in S104 can include the following steps in specific implementation:

[0120] generating a new local grid according to the new position of the target particle, determining the overlapping area and the non-overlapping area of the new local grid and the old local grid;

[0121] interpolating the target solid domain parameter and the target fluid domain parameter to the overlapping area, interpolating the background flow field in the background grid to the non-overlapping area, and taking the interpolated parameters as the solid domain parameter and the fluid domain parameter of the new local grid.

[0122] Specifically, the target solid domain parameter and the target fluid domain parameter calculated at the last step can be interpolated to the overlapping area. For the non-overlapping area, the background flow field is interpolated to initialize the velocity field, and other variables are set to zero to reduce the amount of calculation and maintain the continuity of the solution. After the interpolation is completed, the new local grid replaces the old local grid (the old local grid can be the local grid before the grid reconstruction), and the process reenters the next round of calculation, that is, the solid domain parameter and the fluid domain parameter of the new local grid are input into the fluid-solid coupling model, and then the judgment and other operations are performed.

[0123] By interpolating the calculation results of the last step to the overlapping area of the new local grid and initializing the variables of the non-overlapping area, the continuity of the physical quantities before and after the update of the local grid is ensured, and numerical oscillation is avoided.

[0124] S105: repeating the input and judgment process until the cumulative value of each time step reaches the simulation time length, determining the dynamic characteristics of the target particle in the simulated flow field region according to the target solid domain parameter after the fluid-solid coupling at each time step, the dynamic characteristics at least including the motion trajectory and the stress distribution.

[0125] Specifically, the cumulative value of each time step reaches the simulation time length, that is, wherein n is the number of time steps. is the time step; T is the simulation duration (the total duration of the simulation calculation). When the target solid domain parameters output by the fluid-solid coupling model at each time step are superimposed, the motion trajectory and stress distribution of the target particles in the simulated flow field area are simulated. When , the calculation of the next time step will be continued, forming an iterative calculation process. For example: T = 1 second, = 0.01 seconds, n starts to increase from 0, step 0: when n = 0, the current time Seconds are less than T, step 100: when n=100, the current time seconds, reaches T, and stops the simulation.

[0126] In some embodiments, the above-mentioned S105, based on the target solid domain parameters after fluid-solid coupling at each time step, determines the dynamic characteristics of the target particles in the simulated flow field area. In specific implementation, it may include:

[0127] Superimpose the target motion speed of the target particle at each time step to determine the motion trajectory of the target particle in the simulated flow field area of ​​the target microfluidic chip;

[0128] According to the target left Cauchy Green tensor at each time step, the stress distribution of the target particle in the simulated flow field area of ​​the target microfluidic chip is determined.

[0129] Specifically, the target motion speed of the target particle at each time step can be superimposed to determine the motion trajectory of the target particle in the flow field of the target microfluidic chip (a microfluidic chip with cylindrical obstacles). Figure 3 As shown, Figure 3 There is an inflow from left to right in the image. The initial position of the target particle is on the far left. Every certain time step, the current position of the particle is saved and output. Finally, they are superimposed together to obtain the following: Figure 3 The particle trajectory shown in the flow field, where the circular structure obstacle in the flow field area and the light and dark changes in the flow field area represent the speed of the pure flow field in the chip. Figure 3 u-normed is the normalized velocity in the range of 0-1.93.

[0130] The stress distribution within the target particle can also be determined based on the target left Cauchy Green tensor (i.e., the target solid deformation tensor) at each time step. The target left Cauchy Green tensor output at each time step represents the current deformation of the target particle. Determining the stress distribution within the target particle facilitates a more detailed force analysis of the target particle in the flow field. The target solid domain pressure field and the target fluid domain pressure field can also be superimposed to assist in analyzing the force distribution of the target particle.

[0131] In some embodiments, the above-mentioned dynamic characteristics can also include velocity field distribution, stress distribution evolution, etc., and the dynamic characteristic data can be selected according to actual requirements, and the present specification does not make specific limitations thereon.

[0132] In some embodiments, after determining the motion trajectory of the target particle in the target microfluidic chip simulation flow field region, the target microfluidic chip structure design can be optimized according to the motion trajectory of the target particle. For example, check whether the particle appears to be stranded or the speed is significantly reduced in some areas (such as near the cylindrical obstacle). These areas can cause blockage or efficiency reduction, analyze whether the particle trajectory deviates from the expected path, for example, whether asymmetric motion occurs when bypassing the obstacle, which can affect the separation or detection accuracy. Then, the cylindrical obstacle can be changed to a streamlined shape (such as an elliptical or aerodynamic shape) to reduce vortex and resistance, the obstacle position can also be rearranged to avoid excessive bending or crossing of the particle path, the channel width or height can also be modified to adjust the flow rate distribution, and so on, to ultimately achieve the purpose of optimizing the chip structure.

[0133] In some embodiments, to further improve the stability and robustness in the process of three-dimensional multi-scale solid-fluid coupling calculation, the present application introduces a self-correction method based on a breakpoint continuation mechanism. Key breakpoints can be set during fluid-structure coupling calculation, and information including the current time grid, time step, and variables such as velocity field, pressure field, and deformation field defined on the grid is automatically saved at each breakpoint. Once an abnormal interruption occurs during program running (such as memory overflow, convergence failure, or system failure), the system can automatically restart the calculation based on the latest breakpoint state, avoiding full-time repeated calculation, significantly reducing resource waste, and saving simulation program monitoring costs. At the same time, combined with an abnormal detection module, the fault source can be automatically located and adjusted after an error occurs, with a certain degree of self-adaptive repair capability, thereby enhancing the stability and reliability of the entire solution process. Experiments show that in multiple complex three-dimensional coupling simulations, the breakpoint continuation and self-correction mechanism can reduce resource waste caused by faults by more than 80%, and significantly improve the overall stability of the simulation task.

[0134] Based on the above embodiments, the present application can achieve the following beneficial technical effects:

[0135] The calculation efficiency of multi-scale solid-fluid coupling simulation is improved, specifically, a "background-local" double nested grid structure is adopted, the global calculation domain is divided into a stable background area and a dynamic local high-precision solving area (i.e. the background grid and the local grid are generated), and a small window local updating strategy is introduced (i.e. the moving position of the target particle changes at each time step, and the corresponding local grid is moved or reconstructed accordingly, thereby affecting the input parameters of the next time step), and high-frequency updating is only performed in the area where the physical change is severe. At the same time, the time-discretization optimization of the fluid-structure coupling model can significantly relax the time step while ensuring numerical accuracy, further reducing the computational cost. The combination of the multi-level structure, local space-time refinement and high-order time discretization effectively avoids the waste of resources caused by full-domain recalculation, so that three-dimensional high-precision coupling simulation can be completed on low-core computing platforms, breaking the bottleneck of traditional dependence on high-performance clusters and showing significant engineering practical value.

[0136] The numerical discontinuity problem of pressure at the fluid-structure interface is innovatively solved. On the basis of the local grid, the function space of the pressure is decomposed, the inside and outside of the fluid-structure interface are respectively assigned independent pressure spaces and are respectively calculated and solved, the numerical oscillation and error accumulation caused by the jump of the pressure are avoided, and the numerical stability of the fluid-structure interface region is ensured, thereby providing a new paradigm for multi-physical field strong coupling calculation.

[0137] The method has high universality and engineering adaptability, and the core mechanism supports unified modeling of fluid-structure coupling problems of different physical scales (such as micro-scale biological fluid domains and macro-scale structural domains) and different types of deformation (such as elastic deformation and large displacement rigid body motion). In addition, for complex boundary conditions (such as flow disturbance, wall slip, structure contact, etc.), the method designs a modular boundary processing strategy to ensure accurate transmission and dynamic adaptation of boundary information (such as using the background grid to provide the flow field domain boundary for the local grid). Relying on the above universal coupling framework, the method can be widely used in biological fluid mechanics, aerospace structure response analysis, precision manufacturing process modeling and other key scenes, and has significant technical advancement and cross-industry promotion potential.

[0138] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly describes the difference from other embodiments. Specifically, reference can be made to the description of the related processing of the foregoing related embodiments, which will not be repeated here.

[0139] The above describes the present application, however, it is noted that the specific embodiments are merely for better illustrating the present application and the description is made to the specific embodiments. Other embodiments are within the scope of the appended claims. In some cases, the acts or steps recited in the claims can be performed in a different order than those in the embodiments and still achieve desirable results. In addition, the processes depicted in the figures do not necessarily require the particular order shown or sequential order to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous or possible.

[0140] The above-mentioned multi-scale fluid-structure coupling-based particle dynamic characteristic simulation method will be described below in combination with specific embodiments.

[0141] Reference Figure 4 M bg is a background mesh, M local , M * local is a local mesh established according to the current position of the solid particle. Wherein, the background mesh M bg can provide the boundary of the flow field domain for the local mesh M local , M * local . M local Specifically, it can be an unreconstructed old local mesh, M * local Specifically, it can be a reconstructed new local mesh, for M * local It is necessary to determine the area overlapping with the old local mesh and the area not overlapping with the old local mesh, and mark the overlapping area and the non-overlapping area in M * local , in the overlapping area, the latest time step, such as t n step output of the target solid domain parameter and the target fluid domain parameter can be directly interpolated, in the non-overlapping area, the background flow field in the background mesh can be used to initialize the velocity field, and other variables are assigned to zero, so as to reduce the calculation amount and maintain the continuity of the solution. In each local mesh, fluid-structure coupling solving under multiple time steps is involved, and the process of moving the local mesh after solving. local Involves the process of new mesh (or reconstructed mesh) and interpolation between M * local .

[0142] Specifically, the process of solving the old local mesh and moving the mesh is as follows:

[0143] In time step t n-1 :

[0144] Calculation solving: time step t n-1The fluid-structure coupling input parameters under are input to the fluid-structure coupling model, and the output time step t n-1 Target fluid domain parameters and target solid domain parameters under ;

[0145] Moving mesh: Move solid particles according to the solid particle moving speed in the target solid domain parameters and update the moving position of the solid particles;

[0146] The next time step input parameters are determined: solid particles or M local If the displacement amplitude and deformation degree do not exceed the preset threshold, the time step t n-1 The target fluid domain parameters and target solid domain parameters under the time step t n The fluid-structure interaction input parameters under .

[0147] At time step t n Inside:

[0148] Calculation solution: Set the time step t n The fluid-structure coupling input parameters under are input to the fluid-structure coupling model, and the output time step t n Target fluid domain parameters and target solid domain parameters under ;

[0149] Moving mesh: Move solid particles according to the solid particle moving speed in the target solid domain parameters and update the moving position of the solid particles;

[0150] The next time step input parameters are determined: solid particles or M local If the displacement amplitude and deformation degree exceed the preset threshold, a new local grid M is created. * local , and the time step t n The target fluid domain parameters and target solid domain parameters under the new local grid M are interpolated to * local The overlapping area of ​​the background grid M bg The background flow field in is interpolated to the new local grid M * local In the non-overlapping area, the interpolated parameters are used as the new local grid time step t n The fluid-structure interaction input parameters under .

[0151] The process of solving the new local mesh and moving the mesh is as follows:

[0152] At time step t n Inside:

[0153] Calculation solution: Set the time step t n The fluid-structure coupling input parameters under are input to the fluid-structure coupling model, and the output time step t n Target fluid domain parameters and target solid domain parameters under ;

[0154] Moving mesh: moving the solid particles according to the moving velocity of the solid particles in the target solid domain parameters, updating the moving position of the solid particles;

[0155] Next time step input parameter determination: the displacement amplitude and deformation degree of the solid particles or M * local do not exceed the preset threshold, the target fluid domain parameters and the target solid domain parameters at the time step t n are taken as the fluid-structure coupling input parameters at the time step t n+1 .

[0156] In the time step t n+1 :

[0157] Calculation solving: inputting the fluid-structure coupling input parameters at the time step t n+1 to the fluid-structure coupling model, outputting the target fluid domain parameters and the target solid domain parameters at the time step t n+1 ;

[0158] Moving mesh: moving the solid particles according to the moving velocity of the solid particles in the target solid domain parameters, updating the moving position of the solid particles;

[0159] Next time step input parameter determination: the displacement amplitude and deformation degree of the solid particles or M * local exceed the preset threshold, repeating the above process until the cumulative value of each time step reaches the simulation time length.

[0160] The specific steps of the multi-scale fluid-structure coupling method are as follows:

[0161] (1) Global background flow field construction: generate an overall background mesh in the entire flow passage region to be simulated, and establish the corresponding finite element space. By setting the velocity at the inlet and the no-slip boundary condition on the remaining boundaries, solve a pure Navier-Stokes equation set without solid action items using P2-P1 finite elements. Under the condition of a given appropriate time step, after a sufficient time, a stable background pure flow velocity field is finally obtained, providing basic boundary information for subsequent local calculation.

[0162] (2) Local body-fitted mesh generation and variable initialization: generate a body-fitted local mesh near the current position of the solid particles to be studied, and define variables for describing velocity, pressure and solid structure state on the local mesh. In the initial state, these variables are assigned values according to physical properties.

[0163] (3) Background flow field interpolation to local boundary: interpolate the background velocity field to the boundary of the local mesh as the boundary condition of the fluid region of the local mesh.

[0164] (4) Solving the local coupling equations: After inputting the velocity, pressure and deformation field of the solid at the current moment, the Newton iteration method is used to solve the local fluid-solid coupling equations under the velocity boundary conditions given in (3) to obtain the structural responses such as the velocity, pressure and deformation field of the solid particles and the surrounding flow field at the current time step.

[0165] (5) Structural displacement and grid update: Use the calculated grid velocity field to move the grid points (i.e., move the target particles according to the movement speed of the solid particles) and update the positions of the solid particles.

[0166] (6) Mesh quality check and iterative judgment: Check the displacement amplitude of the solid particles and the degree of mesh deformation at the current time step. If they do not exceed the preset threshold, proceed to the next time step and repeat the above coupling calculation process. If it is judged that the mesh quality is seriously degraded or the solid particle displacement is too large, perform the following mesh reconstruction operation.

[0167] (7) Local body-fitting mesh reconstruction and variable mapping: If the solid particles move significantly or the mesh quality degrades, the system will regenerate a body-fitting mesh at the new position of the solid particles and interpolate the previous calculation results to the overlapping area of ​​the new mesh. For non-overlapping areas, the background flow field is interpolated to initialize the velocity field, and other variables are set to zero to reduce the computational effort and maintain solution continuity.

[0168] (8) Grid update and iteration continue: After the interpolation is completed, the new grid replaces the old grid and the process re-enters the next round of calculation.

[0169] Although this specification provides examples such as the following examples or the accompanying Figure 5 The method operation steps or device structure shown, but based on routine or no creative labor, the method or device may include more or fewer operation steps or module units after partial merger. In the steps or structures that do not logically have a necessary causal relationship, the execution order of these steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiments or drawings of this specification. When the method or module structure described is applied to an actual device, server or terminal product, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiments or drawings (for example, a parallel processor or multi-threaded processing environment, or even a distributed processing or server cluster implementation environment). Based on the above-mentioned particle dynamic characteristics simulation method based on multi-scale fluid-solid coupling, the embodiment of this specification also proposes an embodiment of a particle dynamic characteristics simulation device based on multi-scale fluid-solid coupling. As Figure 5 As shown, the device may specifically include the following modules:

[0170] The background and local grid generation module 501 can be configured to generate a background grid according to a simulation flow field region where the target particle is located, the simulation flow field region having a scale difference with the target particle greater than a preset scale threshold, and generate a local grid according to a position of the target particle, the background grid being used to provide a flow field domain boundary for the local grid.

[0171] The fluid-structure coupling simulation module 502 can be configured to input a solid domain parameter in the current time step local grid and a fluid domain parameter within the flow field domain boundary into a fluid-structure coupling model, and output a target fluid domain parameter and a target solid domain parameter after fluid-structure coupling in the current time step.

[0172] The judgment module 503 can be configured to judge whether the local grid needs to be regenerated according to the target solid domain parameter.

[0173] The input parameter determination module 504 can be configured to, if yes, generate a new local grid according to the target solid domain parameter, and obtain a solid domain parameter and a fluid domain parameter of the new local grid as fluid-structure coupling input parameters in a next time step; and if no, take the target fluid domain parameter and the target solid domain parameter as the fluid-structure coupling input parameters in the next time step.

[0174] The dynamic characteristic determination module 505 can be configured to repeat the process of inputting and judging until a cumulative value of each time step reaches a simulation time length, determine a dynamic characteristic of the target particle in the simulation flow field region according to the target solid domain parameter after fluid-structure coupling in each time step, the dynamic characteristic including at least a motion trajectory and a stress distribution.

[0175] In some embodiments, the background and local grid generation module 501 can be specifically configured to generate an initial local grid according to a position of the target particle, identify a sensitive region and a non-sensitive region in the initial local grid, the sensitive region having a curvature of a fluid-structure interface greater than or equal to a preset curvature threshold, or having a minimum distance of the fluid-structure interface to a calculation domain boundary greater than a preset distance threshold, subdivide grid units in the sensitive region, merge adjacent grid units in the non-sensitive region, and perform quality optimization processing on the grid units in the sensitive region and the non-sensitive region to obtain the local grid.

[0176] In some embodiments, the fluid-structure coupling model in the fluid-structure coupling simulation module 502 can be composed of the following equations:

[0177]

[0178] wherein u is a velocity field of the fluid domain and the solid domain; w t is a motion velocity of the target particle; P s is a pressure field of the solid domain; P fis the pressure field of the fluid domain; Re is the Reynolds number; D is the symmetric gradient tensor of the velocity field; E is the Young's modulus of the target particle; B is the left Cauchy-Green tensor used to describe the deformation of the target particle; I is the unit matrix; T is the simulation time length; is the entire calculation domain composed of the solid domain and the fluid domain; is the solid domain; is the fluid domain; is used to describe the spatial variation of the physical quantity; is used to describe the diffusion process of the physical quantity.

[0179] In some embodiments, the fluid-structure coupling simulation module 502 described above can be specifically configured to determine the intermediate parameters of the solid domain and the intermediate parameters of the fluid domain between the current time step and the next time step based on the solid domain parameters and the fluid domain parameters of the current time step, the scaled time step length being determined by adjusting the time step length by adjusting the parameters; linearly combine the intermediate parameters of the solid domain and the intermediate parameters of the fluid domain with the solid domain parameters and the fluid domain parameters of the current time step to obtain the corrected solid domain parameters and the corrected fluid domain parameters; determine and output the target solid domain parameters and the target fluid domain parameters after fluid-structure coupling based on the corrected solid domain parameters and the corrected fluid domain parameters and the scaled time step length.

[0180] In some embodiments, the solid domain parameters in the fluid-structure coupling simulation module 502 described above can include at least one of the following: the velocity field of the solid domain, the movement speed of the target particle, the pressure field of the solid domain, the Young's modulus of the target particle, the left Cauchy-Green tensor; the fluid domain parameters can include at least one of the following: the velocity field of the fluid domain, the pressure field of the fluid domain, the fluid density, the dynamic viscosity.

[0181] In some embodiments, the judging module 503 described above can be specifically configured to determine the target position of the target particle according to the target movement speed of the target particle; determine the difference between the target position of the target particle and the initial position of the target particle as the displacement amplitude of the target particle, and determine the difference between the target left Cauchy-Green tensor of the target particle and the left Cauchy-Green tensor of the target particle as the deformation degree of the target particle; judge whether the displacement amplitude and the deformation degree exceed the corresponding preset threshold; if yes, it is judged that the local grid needs to be regenerated; if not, it is judged that the local grid does not need to be regenerated.

[0182] In some embodiments, the input parameter determination module 504 described above can be specifically configured to generate a new local grid according to the new position of the target particle, determine the overlapping area and the non-overlapping area of the new local grid and the old local grid; interpolate the target solid domain parameters and the target fluid domain parameters to the overlapping area, interpolate the background flow field in the background grid to the non-overlapping area, and take the interpolated parameters as the solid domain parameters and the fluid domain parameters of the new local grid.

[0183] In some embodiments, the above-mentioned power characteristic determination module 505 can be specifically used for superimposing the target motion speed of the target particle at each time step, determining the motion trajectory of the target particle in the target microfluidic chip simulation flow field region, determining the cumulative deformation of the target particle according to the target left Cauchy Green tensor at each time step, and determining the stress distribution of the target particle in the target microfluidic chip simulation flow field region according to the cumulative deformation.

[0184] As can be seen from the above, the particle power characteristic simulation device based on multi-scale fluid-solid coupling provided by the embodiments of the present specification can solve the problems of low calculation efficiency, poor fluid-solid interface precision and difficulty in matching the interface pressure of multi-scale fluid-solid coupling.

[0185] The embodiments of the present specification also provide an electronic device based on the above-mentioned particle power characteristic simulation method based on multi-scale fluid-solid coupling, which comprises a processor and a memory for storing programs / instructions executable by the processor. When the processor is implemented, the following steps can be performed according to the programs / instructions: generating a background grid according to a simulation flow field region where a target particle is located, generating a local grid according to the position of the target particle, the background grid is used to provide a flow field domain boundary for the local grid, and the simulation flow field region has a scale difference with the target particle greater than a preset scale threshold; inputting the solid domain parameters in the local grid at the current time step and the fluid domain parameters in the flow field domain boundary into a fluid-solid coupling model, outputting the target solid domain parameters and the target fluid domain parameters after fluid-solid coupling at the current time step; determining whether the local grid needs to be regenerated according to the target solid domain parameters; if yes, generating a new local grid according to the target solid domain parameters and obtaining the solid domain parameters and the fluid domain parameters of the new local grid as the fluid-solid coupling input parameters of the next time step; if not, taking the target fluid domain parameters and the target solid domain parameters as the fluid-solid coupling input parameters of the next time step; repeating the inputting and determining process until the cumulative value of each time step reaches the simulation duration, and determining the power characteristics of the target particle in the simulation flow field region according to the target solid domain parameters after fluid-solid coupling at each time step, the power characteristics at least including the motion trajectory and the stress distribution.

[0186] In order to be able to more accurately complete the above-mentioned instructions, referring to Figure 6 The embodiments of the present specification also provide another specific electronic device, as shown in the figure, wherein the electronic device comprises a network communication port 601, a processor 602 and a memory 603, and the above-mentioned structures are connected through internal cables, so that each structure can specifically interact with data.

[0187] The processor 602 can be specifically configured to generate a background grid according to a simulation flow field region where the target particle is located, generate a local grid according to a position of the target particle, the background grid is used to provide a flow field domain boundary for the local grid, and the simulation flow field region has a scale difference greater than a preset scale threshold from the target particle; input a solid domain parameter in the current time step local grid and a fluid domain parameter in the flow field domain boundary to a fluid-solid coupling model, and output a target solid domain parameter and a target fluid domain parameter after fluid-solid coupling in the current time step; determine whether the local grid needs to be regenerated according to the target solid domain parameter; if yes, generate a new local grid according to the target solid domain parameter and obtain a solid domain parameter and a fluid domain parameter of the new local grid as fluid-solid coupling input parameters in a next time step; if no, take the target fluid domain parameter and the target solid domain parameter as the fluid-solid coupling input parameters in the next time step; repeat the inputting and determining process until a cumulative value of each time step reaches a simulation time length, and determine a dynamic characteristic of the target particle in the simulation flow field region according to the target solid domain parameter after fluid-solid coupling in each time step, the dynamic characteristic including a motion trajectory and a stress distribution.

[0188] The memory 603 can be specifically configured to store corresponding instruction programs.

[0189] In the embodiment, the network communication port 601 can be a virtual port that is bound with different communication protocols, so as to send or receive different data. For example, the network communication port can be a port responsible for web data communication, can also be a port responsible for FTP data communication, and can also be a port responsible for mail data communication. In addition, the network communication port can also be an entity communication interface or a communication chip. For example, it can be a wireless mobile network communication chip such as GSM, CDMA, etc.; it can also be a Wifi chip; and it can also be a Bluetooth chip.

[0190] In the embodiment, the processor 602 can be implemented in any appropriate manner. For example, the processor can take the form of, for example, a microprocessor or processor and a computer readable medium storing computer readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, an Application Specific Integrated Circuit (ASIC), a programmable logic controller, and an embedded microcontroller, and the like. The present specification is not limited thereto.

[0191] In the embodiment, the memory 603 can include multiple levels, and can be any memory that can save binary data in a digital system, a circuit without a physical form that has a storage function in an integrated circuit, such as RAM, FIFO, and the like, and a storage device with a physical form in a system, such as a memory stick, a TF card, and the like.

[0192] The embodiment of the present specification also provides a computer storage medium based on the above-mentioned particle dynamic characteristic simulation method based on multi-scale fluid-solid coupling, the computer storage medium stores computer programs / instructions, and when the computer programs / instructions are executed, the following functions are realized: generating a background grid according to a simulation flow field region where a target particle is located, generating a local grid according to a position of the target particle, the background grid is used to provide a flow field domain boundary for the local grid, and a difference between a scale of the simulation flow field region and the target particle is greater than a preset scale threshold; inputting a solid domain parameter in the local grid at a current time step and a fluid domain parameter in the flow field domain boundary into a fluid-solid coupling model, and outputting a target solid domain parameter and a target fluid domain parameter after fluid-solid coupling at the current time step; judging whether the local grid needs to be regenerated according to the target solid domain parameter; if yes, generating a new local grid according to the target solid domain parameter and obtaining a solid domain parameter and a fluid domain parameter of the new local grid as input parameters for fluid-solid coupling at a next time step; if no, taking the target fluid domain parameter and the target solid domain parameter as the input parameters for fluid-solid coupling at the next time step; repeating the inputting and judging process until a cumulative value of each time step reaches a simulation duration, and determining a dynamic characteristic of the target particle in the simulation flow field region according to the target solid domain parameter after fluid-solid coupling at each time step, the dynamic characteristic including a motion trajectory and a stress distribution.

[0193] In the embodiment, the storage medium includes but is not limited to a random access memory (RAM), a read-only memory (ROM), a cache, a hard disk drive (HDD), or a memory card. The memory can be used to store computer program instructions. The network communication unit can be an interface set according to a standard specified by a communication protocol, and is used for network connection communication.

[0194] In the embodiment, the functions and effects realized by the program instructions stored in the computer storage medium can be explained by comparing with other embodiments, and will not be described here.

[0195] Although this specification provides method operation steps as described in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-creative means. The order of steps listed in the embodiments is only one way of executing the steps among many, and does not represent the only execution order. When the device or client product is actually executed, it can be executed in sequence or in parallel according to the method shown in the embodiments or the drawings (for example, in a parallel processor or multi-threaded processing environment, or even a distributed data processing environment). The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, product or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, product or device. Without further restrictions, it is not excluded that there are other identical or equivalent elements in the process, method, product or device including the elements. Words such as first, second, etc. are used to indicate names and do not indicate any particular order.

[0196] Those skilled in the art will also appreciate that, in addition to implementing the controller in pure computer-readable program code, it is entirely possible to implement the same functionality by logically programming the method steps in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, and the like. Therefore, such a controller can be considered a hardware component, and the devices included therein for implementing various functions can also be considered structures within the hardware component. Alternatively, the devices for implementing various functions can be considered both software modules implementing the method and structures within the hardware component.

[0197] This specification may be described in the general context of computer-executable instructions, such as program modules, executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, classes, and the like that perform specific tasks or implement specific abstract data types. This specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media, including storage devices.

[0198] Those skilled in the art can clearly understand the present specification can be implemented by means of software and necessary general hardware platforms through the above description of the embodiments. Based on such understanding, the technical solutions of the present specification can essentially be embodied in the form of a software product. The computer software product can be stored in a storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions to make a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments of the present specification.

[0199] The various embodiments in the present specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. The present specification can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld devices or portable devices, tablet devices, multi-processor systems, microprocessor-based systems, set-top boxes, programmable electronic devices, network PCs, small computers, large computers, distributed computing environments including any of the above systems or devices, etc.

[0200] Although the present specification is described through the embodiments, those skilled in the art know that there are many variations of the present specification without departing from the spirit of the present specification, and it is intended that the appended claims include these variations without departing from the spirit of the present specification.

Claims

1. A particle dynamic characteristics simulation method based on multi-scale fluid-solid coupling, characterized in that: include: Generate a background grid based on the simulated flow field area where the target particle is located, and generate a local grid based on the location of the target particle, wherein the background grid is used to provide a flow field domain boundary for the local grid, and the scale difference between the simulated flow field area and the target particle is greater than a preset scale threshold; Input the solid domain parameters in the local grid of the current time step and the fluid domain parameters within the flow field boundary into the fluid-solid coupling model, and output the target solid domain parameters and target fluid domain parameters after fluid-solid coupling at the current time step; Determining whether a local grid needs to be regenerated according to the target solid domain parameters; If yes, generate a new local grid according to the target solid domain parameters and obtain the solid domain parameters and fluid domain parameters of the new local grid as fluid-solid coupling input parameters for the next time step; if no, use the target fluid domain parameters and target solid domain parameters as fluid-solid coupling input parameters for the next time step; Repeat the input and judgment process until the cumulative value of each time step reaches the simulation time. According to the target solid domain parameters after fluid-solid coupling at each time step, the dynamic characteristics of the target particle in the simulated flow field area are determined. The dynamic characteristics include at least motion trajectory and stress distribution. The fluid-solid coupling model processes the solid domain parameters in the local grid of the current time step and the fluid domain parameters within the flow field domain boundary in the following way: Based on the solid domain parameters and the fluid domain parameters of the current time step, the solid domain intermediate parameters and the fluid domain intermediate parameters between the current time step and the next time step are determined by adjusting the time step by adjusting the parameters; Linearly combine the solid domain intermediate parameters and the fluid domain intermediate parameters with the solid domain parameters and the fluid domain parameters of the current time step to obtain the corrected solid domain parameters and the corrected fluid domain parameters; Based on the modified solid domain parameters and the modified fluid domain parameters, the time step is scaled to determine and output the target solid domain parameters and the target fluid domain parameters after fluid-solid coupling at the current time step; The determining whether the local grid needs to be regenerated according to the target solid domain parameters includes: Determine the target position of the target particle according to the target movement speed of the target particle; Determine the difference between the target position of the target particle and the initial position of the target particle as the displacement amplitude of the target particle, and determine the difference between the target left Cauchy Green tensor of the target particle and the left Cauchy Green tensor of the target particle as the deformation degree of the target particle; Determining whether the displacement amplitude and the deformation degree exceed corresponding preset thresholds; If so, it is determined that the local mesh needs to be regenerated; if not, it is determined that the local mesh does not need to be regenerated.

2. The method according to claim 1, characterized in that Generating a local grid according to the position of the target particle includes: Generate an initial local grid based on the position of the target particles; Identify sensitive areas and insensitive areas in the initial local grid, where the curvature of the sensitive area at the fluid-solid interface is greater than or equal to a preset curvature threshold, or the minimum distance from the fluid-solid interface to the boundary of the computational domain is a preset distance threshold; The grid cells are subdivided in the sensitive area, and the adjacent grid cells are merged in the non-sensitive area. Then, the quality of the grid cells in the sensitive area and the non-sensitive area is optimized to obtain the local grid.

3. The method according to claim 1, characterized in that The fluid-structure interaction model consists of the following equations: Where u is the velocity field of the fluid domain and the solid domain; w t is the moving speed of the target particle; P s is the pressure field of the solid domain; P f is the pressure field of the fluid domain; Re is the Reynolds number; D is the symmetric gradient tensor of the velocity field; E is the Young's modulus of the target particle; B is the left Cauchy Green tensor, which is used to describe the deformation of the target particle; I is the identity matrix; T is the simulation time; The entire computational domain consists of the solid domain and the fluid domain; is a solid domain; is the fluid domain; Used to describe the spatial variation of physical quantities; Used to describe the diffusion process of physical quantities.

4. The method according to claim 1, wherein The solid domain parameters include at least one of the following: the velocity field of the solid domain, the movement velocity of the target particle, the pressure field of the solid domain, the Young's modulus of the target particle, and the left Cauchy Green tensor; the fluid domain parameters include at least one of the following: the velocity field of the fluid domain, the pressure field of the fluid domain, the fluid density, and the dynamic viscosity.

5. The method according to claim 1, wherein The generating of the new local grid and obtaining the solid domain parameters and fluid domain parameters of the new local grid include: Generate a new local grid according to the new position of the target particle, and determine the overlapping area and non-overlapping area between the new local grid and the old local grid; The target solid domain parameters and target fluid domain parameters are interpolated into the overlapping area, the background flow field in the background grid is interpolated into the non-overlapping area, and the interpolated parameters are used as the solid domain parameters and fluid domain parameters of the new local grid.

6. The method according to claim 1, characterized in that Determining the dynamic characteristics of the target particles in the simulated flow field region according to the target solid domain parameters after fluid-solid coupling at each time step includes: Superimpose the target motion speed of the target particle at each time step to determine the motion trajectory of the target particle in the simulated flow field area of ​​the target microfluidic chip; According to the target left Cauchy Green tensor at each time step, the stress distribution of the target particle in the simulated flow field area of ​​the target microfluidic chip is determined.

7. A particle dynamic characteristics simulation device based on multi-scale fluid-solid coupling, characterized in that: include: A background and local grid generation module is used to generate a background grid based on the simulated flow field area where the target particle is located, and to generate a local grid based on the position of the target particle. The background grid is used to provide a flow field domain boundary for the local grid. The scale difference between the simulated flow field area and the target particle is greater than a preset scale threshold. The fluid-solid coupling simulation module is used to input the solid domain parameters in the local grid of the current time step and the fluid domain parameters within the flow field boundary into the fluid-solid coupling model, and output the target fluid domain parameters and target solid domain parameters after fluid-solid coupling at the current time step; A judgment module, configured to judge whether a local grid needs to be regenerated according to the target solid domain parameters; an input parameter determination module for generating a new local grid according to the target solid domain parameters and obtaining the solid domain parameters and fluid domain parameters of the new local grid as fluid-solid coupling input parameters for the next time step; and if not, using the target fluid domain parameters and target solid domain parameters as fluid-solid coupling input parameters for the next time step; A dynamic characteristics determination module is used to repeat the input and judgment process until the cumulative value of each time step reaches the simulation time, and determine the dynamic characteristics of the target particles in the simulated flow field area based on the target solid domain parameters after fluid-solid coupling at each time step. The dynamic characteristics include at least motion trajectory and stress distribution; The fluid-solid coupling model processes the solid domain parameters in the local grid of the current time step and the fluid domain parameters within the flow field domain boundary in the following way: Based on the solid domain parameters and the fluid domain parameters of the current time step, the solid domain intermediate parameters and the fluid domain intermediate parameters between the current time step and the next time step are determined by adjusting the time step by adjusting the parameters; Linearly combine the solid domain intermediate parameters and the fluid domain intermediate parameters with the solid domain parameters and the fluid domain parameters of the current time step to obtain the corrected solid domain parameters and the corrected fluid domain parameters; Based on the modified solid domain parameters and the modified fluid domain parameters, the time step is scaled to determine and output the target solid domain parameters and the target fluid domain parameters after fluid-solid coupling at the current time step; The determining whether the local grid needs to be regenerated according to the target solid domain parameters includes: Determine the target position of the target particle according to the target movement speed of the target particle; Determine the difference between the target position of the target particle and the initial position of the target particle as the displacement amplitude of the target particle, and determine the difference between the target left Cauchy Green tensor of the target particle and the left Cauchy Green tensor of the target particle as the deformation degree of the target particle; Determining whether the displacement amplitude and the deformation degree exceed corresponding preset thresholds; If so, it is determined that the local mesh needs to be regenerated; if not, it is determined that the local mesh does not need to be regenerated.

8. A computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images