Numerical calculation method for underwater explosion bubble movement and related equipment

Abstract

The embodiment of the application discloses a numerical calculation method for underwater explosion bubble movement and related equipment, a grid area is generated, simulation is performed in combination with multiple preset parameters, an area fraction is accurately determined to determine an interface position, geometric method is used to calculate a phase volume fraction flux and iterative simulation is performed, so that the maximum radius of the first pulsation of the bubble in the underwater explosion process and the first pulsation period are obtained, the whole process of the bubble movement can be finely simulated, and the maximum radius and the period of the first pulsation are accurately obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater explosion simulation, in particular to a numerical calculation method for underwater explosion bubble movement and related equipment. BACKGROUND

[0002] Underwater explosion is a physical phenomenon with strong discontinuity and multiphase flow characteristics, and has significant strong nonlinearity and cross-scale characteristics. Underwater explosion involves the formation, propagation of shock waves and their interaction with the surrounding medium and structure, as well as the complex dynamic behavior of the generated bubble of detonation products. The movement of the bubble in the underwater explosion process is affected by many complex factors such as initial conditions, boundary conditions, medium conditions and geometric conditions, and has nonlinear and non-stationary characteristics. It is difficult to comprehensively describe it through simple theoretical formulas, and it is impossible to obtain accurate simulation values of the bubble in the underwater explosion process. SUMMARY

[0003] Therefore, the present application provides a numerical calculation method for underwater explosion bubble movement and related equipment.

[0004] The specific technical scheme of the first embodiment of the present application is: a numerical calculation method for underwater explosion bubble movement, the method comprising: generating a grid region used for simulation according to preset grid parameters; the grid region comprises a plurality of grid units; simulating the underwater explosion bubble movement according to the grid region, preset boundary conditions, preset solving parameters and preset material parameters, obtaining the area fraction information of each grid unit and the pulsation radius of the bubble at the initial simulation time; the area fraction information is the area ratio of water and bubble; obtaining the interface position of each grid unit according to the area fraction information and the grid scale in the preset grid parameters, and simulating the underwater explosion bubble movement based on the interface position; calculating the phase volume fraction flux of each grid unit after fluid flow at the next simulation time according to the interface position of all grid units and the geometric method; the fluid includes water and bubble; taking the phase volume fraction flux as the area fraction information of the grid unit at the next simulation time, returning to the step of obtaining the normal vector of the interface between water and bubble of each grid unit according to the area fraction information and the grid scale in the preset grid parameters, until the simulation ends, outputting the simulation result, the simulation result includes the maximum radius of the first pulsation of the bubble in the underwater explosion process and the first pulsation period.

[0005] Preferably, the interface position of each grid unit is obtained according to the area fraction information and the grid scale in the preset grid parameters, comprising: obtaining the normal vector of the interface between water and bubble of each grid unit according to the area fraction information and the grid scale in the preset grid parameters; obtaining the interface position of each grid unit according to the normal vector and the area fraction information.

[0006] Preferably, the normal vector is obtained by the following formula:

[0007]

[0008]

[0009] wherein, is the x-direction component of the normal vector of the grid point i , j is the y-direction component of the normal vector of the grid point , i , j is the grid scale in the x-direction, is the grid scale in the y-direction, is the volume fraction of water phase. Preferably, the method for calculating the phase volume fraction flux of each grid cell after fluid flow at the next simulation time according to the interface position and geometry of all grid cells comprises: integrating the interface position of all grid cells to obtain the phase interface of the flow field during the movement of the underwater explosion bubble at the initial simulation time; and calculating the phase volume fraction flux of each grid cell after fluid flow at the next simulation time by a geometry method based on the phase interface of the flow field.

[0010] Preferably, the grid region is a grid region with gradually changing size.

[0011] Preferably, the size of the grid region with gradually changing size is obtained by the following formula:

[0012]

[0013] wherein,

[0014] is the size of the n+1 grid, is the size of the n grid, is the preset gradient rate. Preferably, the minimum size of the grid region with gradually changing size is obtained by the following formula:

[0015]

[0016] wherein,

[0017] is the minimum size of the grid, is the preset terminal coordinate of the grid region, is the preset starting coordinate of the grid region, is the preset grid cell change rate, is the n grid.

[0018] ​The specific technical scheme of the second embodiment of the present application is: a numerical calculation system for underwater explosion bubble movement, the system comprises: a grid generation module, a simulation module, an interface position acquisition module, a phase volume fraction flux calculation module and an iterative calculation module; the grid generation module is used to generate a grid area used for simulation according to preset grid parameters; the grid area comprises a plurality of grid units; the simulation module is used to simulate the underwater explosion bubble movement according to the grid area, preset boundary conditions, preset solving parameters and preset material parameters, to obtain area fraction information of each grid unit at an initial simulation time and a pulsation radius of the bubble; the area fraction information is an area ratio of water and the bubble; the interface position acquisition module is used to obtain an interface position of each grid unit according to the area fraction information and a grid scale in the preset grid parameters, and to simulate the underwater explosion bubble movement based on the interface position; the phase volume fraction flux calculation module is used to calculate phase volume fraction fluxes of the grid units after fluid flow at a next simulation time according to the interface positions of all the grid units and a geometric method; the fluid comprises water and the bubble; the iterative calculation module is used to return the step of obtaining a normal vector of an interface between water and the bubble of each grid unit according to the area fraction information and the grid scale in the preset grid parameters, taking the phase volume fraction fluxes as the area fraction information of the grid units at the next simulation time, until simulation ends, and outputting a simulation result, the simulation result comprising a maximum radius of first pulsation of the bubble and a first pulsation period in the underwater explosion process.

[0019] The specific technical scheme of the third embodiment of the present application is: a numerical calculation device for underwater explosion bubble movement, comprising a memory and a processor, the memory stores a computer program, and the computer program is executed by the processor to make the processor execute the steps of the method in any one of the first embodiments of the present application.

[0020] The specific technical scheme of the fourth embodiment of the present application is: a computer readable storage medium, storing a computer program, the computer program is executed by the processor to make the processor execute the steps of the method in any one of the first embodiments of the present application.

[0021] The implementation of the embodiments of the present application will have the following beneficial effects:

[0022] The present application generates a grid area, combines a plurality of preset parameters for simulation, accurately determines the interface position by using the area fraction, and then calculates the phase volume fraction flux by a geometric method and iteratively simulates, so as to obtain the maximum radius of first pulsation of the bubble and the first pulsation period in the underwater explosion process. The present application can simulate the whole process of bubble movement in detail and accurately obtain the maximum radius of first pulsation and the period. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only only some embodiments of the present application, and do not represent all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] Figure 1 Flow chart for numerical calculation method of underwater explosion bubble movement;

[0025] Figure 2 Schematic diagram of normal vector;

[0026] Figure 3 Schematic diagram of the composition of the numerical calculation platform for underwater explosion bubble movement;

[0027] Figure 4 Schematic diagram of uniform size grid;

[0028] Figure 5 Schematic diagram of local encryption grid;

[0029] Figure 6 Schematic diagram of gradually changing size grid;

[0030] Figure 7 Schematic diagram of numerical prediction of bubble change process;

[0031] Figure 8 Schematic diagram of bubble volume change curve;

[0032] Figure 9 Schematic diagram of bubble radius change curve;

[0033] Figure 10 Schematic diagram of the structure of the numerical calculation system for underwater explosion bubble movement;

[0034] Among them, 201, grid generation module; 202, simulation module; 203, interface position acquisition module; 204, phase volume fraction flux calculation module; 205, iterative calculation module. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] The terms "first", "second", and the like in the description and in the claims of the present application and the drawings mean for distinguishing different objects, not for describing a particular sequential order. Moreover, the terms "comprises", "comprising", and the like in the present description are used to mean not only "includes" or "including", but also "consisting of" and / or "consisting essentially of". For example, a process, method, article, or apparatus that comprises a list of steps or elements is not necessarily limited to the listed steps or elements, but can optionally include additional steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

[0037] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from among a great variety of embodiments that can be made.

[0038] Reference is made to Figure 1 A flow chart of steps of a numerical calculation method of underwater explosion bubble motion in a first embodiment of the application is shown in Fig. 1 to accurately obtain the maximum radius and period of the first pulsation. The method comprises:

[0039] Step 101: generating a grid region for simulation according to preset grid parameters; the grid region comprises a plurality of grid units;

[0040] Step 102: simulating the underwater explosion bubble motion according to the grid region, preset boundary conditions, preset solving parameters, and preset material parameters to obtain area fraction information of each grid unit at an initial simulation time and a pulsation radius of the bubble; the area fraction information is an area ratio of water and the bubble;

[0041] Step 103: obtaining an interface position of each grid unit according to the area fraction information and a grid scale in the preset grid parameters, and simulating the underwater explosion bubble motion based on the interface position;

[0042] Step 104: calculating a phase volume fraction flux of each grid unit after fluid flow at a next simulation time according to the interface positions of all the grid units and a geometric method; the fluid comprises water and the bubble;

[0043] Step 105: taking the phase volume fraction flux as the area fraction information of the grid unit at the next simulation time, returning to the step of obtaining a normal vector of the interface between water and the bubble of each grid unit according to the area fraction information and the grid scale in the preset grid parameters, until the simulation ends, and outputting a simulation result, the simulation result comprising a maximum radius and a period of the first pulsation of the bubble in the underwater explosion process.

[0044] Specifically, according to preset grid parameters, such as the interval, range, etc. of the grid, a grid area for simulating the motion of the underwater explosion bubble is generated, which is composed of a plurality of grid units. The preset boundary conditions, such as the fixed or moving conditions of the water boundary; the preset solving parameters, such as the time step of calculation, the convergence accuracy, the preset material parameters, covering the density, viscosity and other physical properties of water and bubble, are introduced into the simulation model together with the generated grid area to simulate the motion of the underwater explosion bubble, so that the area fraction information of each grid unit at the initial simulation time, i.e. the area ratio of water and bubble, is obtained, and the pulsation radius of the bubble is also obtained. The interface position of water and bubble in each grid unit is determined by using the area fraction information and the preset grid scale, and the simulation of the motion of the underwater explosion bubble is continuously promoted based on the interface position. By means of geometric method, the phase volume fraction flux of each grid unit after the fluid (including water and bubble) flows at the next simulation time is calculated based on the interface position of all grid units. The calculated phase volume fraction flux is taken as the area fraction information of the grid unit at the next simulation time, and the step of obtaining the interface position is returned again, and the iteration is repeated in this way. When the simulation reaches the preset end condition, the calculation is stopped, and the simulation result is output, and the maximum radius of the first pulsation of the bubble and the first pulsation period in the underwater explosion process are obtained, which provides data support for in-depth research and application of the motion characteristics of the underwater explosion bubble.

[0045] The method generates a grid area, combines a plurality of preset parameters for simulation, accurately determines the interface position by using the area fraction, and iteratively simulates the phase volume fraction flux by using the geometric method, so as to obtain the maximum radius of the first pulsation of the bubble and the first pulsation period in the underwater explosion process. The method can simulate the whole process of the bubble motion in detail and accurately obtain the maximum radius and period of the first pulsation.

[0046] In specific embodiments, the interface position of each grid unit is obtained according to the area fraction information and the grid scale in the preset grid parameters, which includes: obtaining the normal vector of the interface between water and bubble in each grid unit according to the area fraction information and the grid scale in the preset grid parameters; and obtaining the interface position of each grid unit according to the normal vector and the area fraction information. Specifically, the schematic diagram of the normal vector is shown in Figure 2After determining the interface normal vector, a straight line with that normal vector is moved within each grid cell. The solution is iteratively calculated based on the area fraction information of each grid cell crossing the interface, ensuring that the area of ​​water and gas cut by the straight line matches the known phase volume fraction within the grid. Based on the calculated normal vector and interface position, a straight line segment is used to represent the interface within each grid cell. These line segments from all grid cells together construct the phase interface of the entire flow field. After interface reconstruction, the phase volume fraction flux caused by fluid flow is calculated using geometric methods, and the volume fraction field for the next time step is updated, thereby simulating the motion and changes of the interface.

[0047] In a specific embodiment, the normal vector is obtained using the following formula:

[0048]

[0049]

[0050] in, For grid points ( i , j The x-direction component of the normal vector of ). For grid points ( i , j The y-direction component of the normal vector of ). is the grid scale in the x-direction. y is the grid scale. This represents the volume fraction of the aqueous phase.

[0051] In a specific embodiment, the step of calculating the phase volume fraction flux of each grid cell after fluid flow at the next simulation moment based on the interface positions of all grid cells and geometric methods includes: integrating the interface positions of all grid cells to obtain the phase interface of the flow field during the underwater explosion bubble motion at the initial simulation moment; and calculating the phase volume fraction flux of each grid cell after fluid flow at the next simulation moment using geometric methods based on the phase interface of the flow field. Specifically, the interface positions of all grid cells are integrated. The interface information determined by each grid cell is summarized to construct the phase interface of the flow field during the underwater explosion bubble motion at the initial simulation moment. This phase interface can intuitively show the distribution and boundary of water and bubbles in the flow field. Based on the constructed flow field phase interface, geometric methods are used for calculation, such as using relevant geometric algorithms for flux calculation, and based on the morphology and position of the phase interface and the flow characteristics of the fluid, the phase volume fraction flux corresponding to each grid cell after fluid (including water and bubbles) flow at the next simulation moment is accurately calculated.

[0052] In specific embodiments, the grid region is a gradually changing size grid region. When a uniform size grid is needed to be generated, only the number of nodes in the x-axis, y-axis and z-axis in the coordinate system needs to be given , the number of units is , and the size of the grid is the coordinate span divided by the number of units. When a gradually changing size grid is needed to be generated, the proportion of the grid size change needs to be added .

[0053] In specific embodiments, the size of the gradually changing size grid region is obtained by the following formula:

[0054]

[0055] wherein, is the size of the n+1th grid, is the size of the nth grid, is a preset change rate.

[0056] In specific embodiments, the minimum size of the gradually changing size grid region is obtained by the following formula:

[0057]

[0058] wherein, is the minimum size of the grid, is a preset end coordinate of the grid region, is a preset start coordinate of the grid region, is a preset grid unit change rate, is the nth grid.

[0059] Specifically, starting from the working condition of the underwater explosion to be simulated, the boundary of the calculation domain is determined, and the three-axis coordinate values of the calculation domain boundary in a certain coordinate system are determined. The grid is generated by using the coordinate parameters, the lower limit of the coordinate value is taken as the starting point of the grid node, and the upper limit of the coordinate axis is taken as the end point of the grid node. When a uniform size grid is needed to be generated, only the number of nodes in the x-axis, y-axis and z-axis in the coordinate system needs to be given , the number of units is , and the size of the grid is the coordinate span divided by the number of units.

[0060] When a gradually changing size grid is needed to be generated, the proportion of the grid size change needs to be added , when the grid size gradually increases, the calculation formula of the size is , and when the grid size gradually decreases, the calculation formula of the size is .

[0061] The calculation formula of the minimum size of the grid is .

[0062] When , , the cell size increases at a gradual rate .

[0063] When , , the cell size decreases at a gradual rate .

[0064] Overall, starting from the smallest cell, the cell size increases .

[0065] Fluids are simulated using a constitutive model and equation of state, water and gas generated by explosion are defined as two immiscible fluids, a piecewise linear interface reconstruction method is used to capture the interface between the bubble and water medium, in two-dimensional case, a series of straight line segments are used to approximate the complex phase interface, in three-dimensional case, a series of plane slices are used to approximate the complex phase interface, a volume fraction is used to represent the existence of phase in each grid cell, and the interface is reconstructed based on the volume fraction field. The normal vector of the interface in each cell is calculated based on the gradient of the volume fraction value of the surrounding grid cells, so as to estimate the direction of the interface. Taking a two-dimensional cell as an example, the normal vector thereof is:

[0066]

[0067]

[0068] In the formula, and are grid coordinates; is the volume fraction of the main phase; and are grid scales.

[0069] After determining the normal vector of the interface, a straight line with the normal is moved in each grid, and the area fraction information of each grid cell across the interface is iteratively solved, so that the area of water and the area of gas cut by the straight line match the known phase volume fraction in the grid.

[0070] According to the calculated normal vector and the position of the interface, the interface is represented by a straight line segment in each grid, and all the line segments in the grids jointly piece together the phase interface of the entire flow field.

[0071] After the interface reconstruction is completed, the phase volume fraction flux caused by fluid flow is calculated by a geometric method, and the volume fraction field of the next time step is updated, so as to simulate the movement and change of the interface.

[0072] The filling of the charge is performed using the geometric parameter method. Generally, the shape of the charge is regular. When the shape of the charge is a sphere, the center coordinates and the radius of the sphere are defined to determine the structural parameters of the explosive. When the shape of the charge is a cube, the center coordinates and the side length of the cube are defined to determine the structural parameters of the explosive. When the shape of the charge is a cylinder, the center coordinates, the inner diameter, the outer diameter and the height of the cylinder are defined to determine the structural parameters of the charge. The constitutive model and the equation of state are used to describe the fluid materials such as explosives and water. The constitutive model is a mathematical expression for describing the mechanical properties of materials, such as stress, strain, strength and time, which is used to characterize the mechanical behavior of materials under different conditions. The equation of state is an expression for describing the physical properties of materials under different conditions, which is used to characterize the relationship between the thermodynamic parameters such as pressure, density and temperature in the fluid. In solid materials, the equation of state can reflect the fluid elastoplasticity of the material under strong impact. The initial unit volume explosion energy of the explosive is the combustion value multiplied by the density, for example, when the explosive material is TNT, the initial unit volume explosion energy of the explosive is .

[0073] For different working conditions, only the relevant parameters need to be modified, which facilitates the secondary development of the program and reduces the time of numerical modeling when large-scale calculation is performed. The piecewise linear interface reconstruction method can produce sharp interface representation, improve the accuracy of interface curvature calculation, and thus more accurately calculate the surface tension effect, realize accurate description of the phase interface (accurately capture the details and dynamic changes of the phase interface), reduce numerical diffusion, ensure calculation accuracy, and greatly reduce the difficulty of interface reconstruction. The charge is defined by geometric parameters, which can realize numerical simulation of multiple explosive sources, and the initiation time and explosion water depth of the multiple explosive sources are controllable. The modules and parameter transmission are clear, which facilitates the understanding and use of the developer.

[0074] Figure 3 The composition modules of the numerical calculation platform for the motion of the bubble of underwater explosion are shown, mainly including the calculation grid generation module, the boundary condition setting module, the material parameter setting module and the solving parameter setting module, Figure 4 The uniform size grid is shown, Figure 5 The local encryption grid is shown, Figure 6 The gradually changing size grid is shown.

[0075] The numerical calculation condition is that the calculation domain is a square with a side length of 1 m, the explosive material is TNT, the mass is 43.05 g, the shape of the charge is spherical, and the explosion water depth is 0.5 m.

[0076] Firstly, the size parameters of the calculation domain are input into the grid generation module, and the center of the cubic calculation domain is defined as the coordinate origin. In this example, the grid density is consistent along the three coordinate axes. In the x-axis, y-axis and z-axis directions, the position coordinates of node 1 are defined as -0.5 m, and the position coordinates of node 101 are defined as 0.5 m. The 101 nodes can form 100 grid units, and the size of each unit is 0.01 m. The total number of grid units is 100x100x100, i.e. one million units, and the generated grid is as shown in FIG. 1. Figure 4

[0077] When a local encryption region needs to be generated, the spatial region that needs to be encrypted is first determined, for example, a cubic grid encryption region with a center and a side length of 0.5 m is determined in the above cubic grid region with a side length of 1 m. In the x-axis, y-axis and z-axis directions, the position coordinates of node 1 are defined as -0.5 m, the position coordinates of node 11 are defined as -0.25 m, the position coordinates of node 91 are defined as 0.25 m, and the position coordinates of node 101 are defined as 0.5 m. In space, the grid size of the non-encrypted region is 0.025 m, and the grid size of the encrypted region is 0.00625 m. Since the number of nodes remains unchanged, the total number of grid units is also one million, and the generated grid is as shown in FIG. 2. Figure 5

[0078] When a size-varying grid needs to be generated, the proportion of grid size variation is first determined, for example, a grid with gradually decreasing size from the outside to the inside of the grid is generated in the above cubic grid region with a side length of 1 m. In the x-axis, y-axis and z-axis directions, the position coordinates of node 1 are defined as -0.5 m, the position coordinates of node 51 are defined as 0 m, and the position coordinates of node 101 are defined as 0.5 m. In the interval [-0.5, 0], the proportion of grid size variation is -0.1, and the grid size gradually decreases. In the interval [0, 0.5], the proportion of grid size variation is 0.1, and the grid size gradually increases. The total number of grid units is also one million, and the generated grid is as shown in FIG. 3. In this example, a size-varying grid is used. Figure 6

[0079] After the calculation grid is generated, the boundary condition setting module is used to define the environmental pressure. The node at the top of the calculation domain is defined as the reference point, and the reference pressure is set. When the top of the calculation domain is air, the reference pressure is set to one standard atmosphere. When simulating a deep water explosion, the reference pressure is set to the corresponding hydrostatic pressure. The hydrostatic pressure distribution in the calculation domain can be solved by the hydrostatic pressure calculation formula. Then, the charge is filled. The charge is spherical, and only the center coordinates and the radius of the sphere need to be defined to determine the geometric structure of the charge. The center coordinates of the charge are (0, 0, 0), and the radius of the charge can be inversely solved according to the density of TNT as 0.0185 m. The initiation time is defined as 0 ms, and the explosion depth is 0.5 m.​​​

[0080] Further, the material parameters of water, detonation products and the like are set, the air material model is combined with the state equation to describe the water, detonation products and the like, the air material model avoids the calculation of fluid material shear stress in the calculation, and the state equation describes the relationship between the fluid pressure and the volume, temperature and the like in the simulation. After the material parameter setting is completed, the segmented linear interface reconstruction method is used to capture the movement change of the phase interface. Finally, the parameters such as the simulation time, time step, calculation energy and data output sampling frequency are defined, and the solver is submitted for calculation, and after the solving is completed, the data processing module is imported for data processing and analysis. Figure 7 The numerical prediction bubble change process is shown, Figure 8 The bubble volume change is shown, Figure 9 The bubble radius change is shown. As can be seen from the figure, the volume of the bubble first increases and then decreases, which reflects the pulsating motion of the bubble, and the cycle of the bubble pulsation is clear. At the same time, due to the existence of the buoyancy, the position of the bubble center moves upward, which reflects the migration motion of the bubble. The present application can better predict the pulsating motion and migration motion of the bubble in the underwater explosion process.

[0081] In specific embodiments, please refer to Figure 10 , it is a structure schematic diagram of a kind of numerical calculation system of underwater explosion bubble motion in the second embodiment of the present application, and the numerical calculation system of underwater explosion bubble motion exists in Figure 3The system comprises a material parameter setting module in the system, the system comprises a grid generation module 201, a simulation module 202, an interface position acquisition module 203, a phase volume fraction flux calculation module 204 and an iterative calculation module 205; the grid generation module 201 is used for generating a grid area used for simulation according to preset grid parameters; the grid area comprises a plurality of grid units; the simulation module 202 is used for simulating the underwater explosion bubble movement according to the grid area, a preset boundary condition, a preset solving parameter and a preset material parameter, obtaining area fraction information of each grid unit at an initial simulation moment and a pulsation radius of the bubble; the area fraction information is an area ratio of water and the bubble; the interface position acquisition module 203 is used for acquiring an interface position of each grid unit according to the area fraction information and a grid scale in the preset grid parameters, and simulating the underwater explosion bubble movement based on the interface position; the phase volume fraction flux calculation module 204 is used for calculating phase volume fraction fluxes of all grid units after fluid flow at a next simulation moment according to the interface positions of the grid units and a geometric method; the fluid comprises water and the bubble; the iterative calculation module 205 is used for taking the phase volume fraction fluxes as the area fraction information of the grid units at the next simulation moment, returning the step of obtaining a normal vector of an interface between water and the bubble of each grid unit according to the area fraction information and the grid scale in the preset grid parameters until simulation ends, outputting a simulation result, and the simulation result comprises a maximum radius of the first pulsation of the bubble in the underwater explosion process and a first pulsation period.

[0082] The system generates a grid area, combines a plurality of preset parameters to perform simulation, accurately determines an interface position by using area fraction, and iteratively simulates by calculating phase volume fraction fluxes through a geometric method, so that the maximum radius of the first pulsation of the bubble in the underwater explosion process and the first pulsation period are obtained.

[0083] In specific embodiments, the third embodiment of the present application provides a numerical calculation device for underwater explosion bubble movement, comprising a memory and a processor, the memory stores a computer program, and the computer program is executed by the processor to make the processor execute the steps of the method in any one of the first embodiment of the present application.

[0084] In specific embodiments, the fourth embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to make the processor execute the steps of the method in any one of the first embodiment of the present application.

[0085] The above embodiments only express several implementation ways of the present application, and the description is specific and detailed, but it should not be understood as a limitation to the patent scope of the present application. It should be noted that, for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

[0086] The above is only the preferred embodiment of the present application, and is not a limitation on other forms of the present application. Any skilled in the art can use the disclosed technical content to make changes or modifications to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solution content of the present application still belongs to the protection scope of the technical solution of the present application.

Claims

1. A method of numerically calculating motion of a bubble of underwater explosion, characterized by, The method comprises: generating a grid region for simulation according to preset grid parameters; the grid region comprises a plurality of grid units; simulating underwater explosion bubble movement according to the grid region, preset boundary conditions, preset solving parameters and preset material parameters to obtain area fraction information of each grid unit at an initial simulation time and a pulsation radius of the bubble; the area fraction information is an area ratio of water and the bubble; obtaining a normal vector of an interface between water and the bubble of each grid unit according to the area fraction information and a grid size in the preset grid parameters; obtaining an interface position of each grid unit according to the normal vector and the area fraction information, and simulating underwater explosion bubble movement based on the interface position; calculating a phase volume fraction flux of each grid unit after fluid flow at a next simulation time according to the interface positions of all the grid units and a geometric method; the fluid comprises water and the bubble; taking the phase volume fraction flux as the area fraction information of the grid unit at the next simulation time, returning to the step of obtaining the interface position of each grid unit according to the area fraction information and the grid size in the preset grid parameters until simulation is completed, and outputting a simulation result; the simulation result comprises a maximum radius of a first pulsation of the bubble and a first pulsation period in the underwater explosion process.

2. The numerical calculation method of bubble motion of underwater explosion according to claim 1, wherein, The normal vector is obtained by using the following formula: wherein is the x-direction component of the normal vector of the grid point i , j is the y-direction component of the normal vector of the grid point , i is the x-direction component of the normal vector of the grid point j , is the x-direction grid scale, is the y-direction grid scale, is the water phase volume fraction.

3. The numerical calculation method of underwater explosion bubble motion according to claim 1, characterized in that, The calculation of the phase volume fraction flux of each grid unit after fluid flow at a next simulation time according to the interface positions of all the grid units and a geometric method comprises: integrating the interface positions of all the grid units to obtain a phase interface of a flow field during underwater explosion bubble movement at an initial simulation time; calculating the phase volume fraction flux of each grid unit after fluid flow at a next simulation time based on the phase interface of the flow field by using a geometric method.

4. The numerical calculation method of underwater explosion bubble motion according to claim 1, characterized in that, The grid region is a grid region with gradually changing sizes.

5. The numerical calculation method of underwater explosion bubble motion according to claim 4, characterized in that, The size of the grid region with gradually changing sizes is obtained by using the following formula: wherein, is the size of the n+1 grid, is the size of the n grid, is a preset gradient rate.

6. The numerical calculation method of underwater explosion bubble motion according to claim 4, wherein, The minimum size of the grid region with gradually changing sizes is obtained by using the following formula: wherein, is the minimum size of the grid, is the preset end coordinates of the grid area, is the preset start coordinates of the grid area, is the preset grid cell change rate, is the nth grid.

7. An underwater explosion bubble motion numerical calculation system characterized by comprising: The system comprises a grid generation module, a simulation module, an interface position acquisition module, a phase volume fraction flux calculation module and an iterative calculation module. The grid generation module is configured to generate a grid region for simulation according to preset grid parameters; the grid region comprises a plurality of grid units. The simulation module is configured to simulate underwater explosion bubble movement according to the grid region, preset boundary conditions, preset solving parameters and preset material parameters to obtain area fraction information of each grid unit at an initial simulation time and a pulsation radius of the bubble; the area fraction information is an area ratio of water and the bubble. The interface position acquisition module is configured to obtain a normal vector of an interface between water and the bubble of each grid unit according to the area fraction information and a grid size in the preset grid parameters; obtain an interface position of each grid unit according to the normal vector and the area fraction information, and simulate underwater explosion bubble movement based on the interface position. The phase volume fraction flux calculation module is configured to calculate a phase volume fraction flux of each grid unit after fluid flow at a next simulation time according to the interface positions of all the grid units and a geometric method; the fluid comprises water and the bubble. The phase volume fraction flux calculation module is configured to calculate phase volume fraction fluxes of the grid cells after fluid flow at a next simulation time according to interface positions and geometric methods of all the grid cells; the fluid includes water and bubbles; The iterative calculation module is configured to return the step of obtaining a normal vector of an interface between water and bubbles of each grid cell according to the area fraction information and a grid scale in preset grid parameters until a simulation ends, and output a simulation result including a maximum radius of a first pulsation of a bubble and a first pulsation period in a water explosion process.

8. An apparatus for numerical calculation of underwater explosion bubble motion, comprising a memory and a processor, characterized in that, The memory stores a computer program, and the computer program, when executed by the processor, causes the processor to perform the steps of the method in any one of claims 1 to 6.

9. A computer readable storage medium storing a computer program, characterized in that, The computer program, when executed by the processor, causes the processor to perform the steps of the method in any one of claims 1 to 6.

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