Blade fluid-structure coupling analysis method based on acoustic unit self-adaptation and related device

Abstract

The application provides a blade fluid-structure coupling analysis method and system based on acoustic unit self-adaptation, an electronic device and a storage medium. The method generates corresponding grids by constructing a geometric model and discretizing; converts the first fluid domain grid into an acoustic fluid unit grid with only pressure degrees of freedom; constructs a mapping fidelity index based on the geometric deviation of the interface nodes and the load projection error; and performs adaptive grid refinement and iterative update. The second fluid domain grid is used to solve the transient flow field to obtain the fluid load; a geometrically coincident but logically independent acoustic-structure coupling interface and fluid load interface are constructed, the former introduces fluid added mass to construct the system mass matrix, and the latter maps the fluid load as an excitation force; and the transient dynamic equation is solved under a one-way coupling framework to obtain the transient response of the underwater blade. The application introduces the added mass effect while maintaining the high efficiency of one-way coupling, solving the problem that calculation efficiency and prediction accuracy are difficult to balance.

Description

Technical Field

[0001] This invention relates to the field of hydraulic machinery dynamics simulation technology, and in particular to a blade fluid-structure interaction analysis method, system, electronic device and storage medium based on acoustic unit adaptive fluid-structure interaction. Background Technology

[0002] Fluid-structure interaction (FSI) is widespread in hydraulic machinery such as turbines, pumps, and marine propellers. The core component of these machines—the blades—is constantly surrounded by a high-density fluid medium during operation. The dynamic effects of the fluid on the blade structure are not only manifested in unsteady water pressure loads but also in the complex coupling effects between fluid and structural vibrations. Especially for large-sized, thin-walled modern blade structures, the fluid environment significantly alters the system's dynamic characteristics. When underwater blades vibrate, they cause the surrounding fluid to accelerate. This fluid inertia effect manifests as added mass in the dynamic equations. Studies show that the added mass causes the structure's natural frequency in water to be significantly lower than in air, resulting in a "frequency shift." Currently, FSI analysis methods for hydraulic machinery blades mainly fall into two categories: two-way coupling and one-way coupling. Two-way FSI methods simultaneously solve the fluid domain governing equations and the structural domain governing equations, repeatedly exchanging fluid load and structural displacement information at the interface at each time step until convergence. While this method can fully consider the interaction between the fluid and the structure, including the added mass effect, it is not universally applicable. However, its computational cost is extremely high; a typical transient analysis often requires weeks or even months of computation time, making it difficult to meet the requirements of engineering research and development cycles. Furthermore, two-way coupling is highly sensitive to mesh quality, time step size, and convergence criteria, exhibiting poor computational stability, which limits its widespread application in industry. One-way fluid-structure interaction (FSI) decouples fluid analysis from structural analysis. It first obtains the unsteady pressure distribution on the blade surface through computational fluid dynamics, and then applies this pressure as an external load to the structural finite element model for dynamic solution. Because it avoids repeated data exchange and iterative solutions, one-way coupling is far more computationally efficient than two-way coupling and is currently the most commonly used method in engineering applications. However, traditional one-way FSI methods typically employ a "dry modal" analysis approach, meaning that when solving the dynamic equations, the structural side only includes its own mass matrix, completely ignoring the "frequency shift" effect of the added mass of the water on the modal frequencies. While this simplified approach offers high computational efficiency, it fails to reflect the fundamental changes in the inherent properties of the structure caused by the fluid environment. This leads to serious distortion risks in resonance prediction and transient response analysis, often overestimating the structure's natural frequencies and overlooking potential low-frequency resonance hazards. In conclusion, for the practical engineering development of modern hydraulic machinery, there is an urgent need for a fluid-structure interaction simulation strategy that combines high computational efficiency with high physical fidelity; however, existing traditional analysis methods often suffer from a technical bottleneck where it is difficult to balance speed and accuracy. Summary of the Invention

[0003] This invention provides a blade fluid-structure interaction analysis method, system, electronic device, and storage medium based on acoustic unit adaptation. It addresses the shortcomings of traditional blade fluid-structure interaction analysis methods, which cannot achieve high-fidelity fluid-added mass effect introduction that matches the actual vibration mode of the blade while maintaining high computational efficiency of unidirectional coupling. This results in a trade-off between the prediction accuracy and computational efficiency of underwater blade dynamic response.

[0004] This invention provides a blade fluid-structure interaction analysis method based on acoustic unit adaptation, comprising: A geometric model comprising a blade structural domain, a first fluid domain, and a second fluid domain is constructed. The blade structural domain, the first fluid domain, and the second fluid domain are discretized to generate blade structural meshes, first fluid domain meshes, and second fluid domain meshes, respectively. Based on the coupling solution requirements, the fluid elements in the first fluid domain mesh are adaptively converted into an acoustic fluid element mesh with only pressure degrees of freedom; Based on the second fluid domain mesh, perform transient flow field pre-solution to obtain the initial transient fluid load distribution acting on the blade structure surface; Based on the initial transient fluid load distribution and the blade structure mesh, the nodal geometric deviation and load projection error of the acoustic fluid element mesh and the blade structure mesh at the interface are calculated, and the interface mapping fidelity index is constructed based on the nodal geometric deviation and load projection error. When the interface mapping fidelity index is lower than the preset threshold, adaptive mesh refinement is performed on the local area of ​​the error concentration, and the calculation and refinement process is repeated until the interface mapping fidelity index reaches or exceeds the preset threshold, so that the acoustic fluid element mesh and the blade structure mesh can adaptively achieve topological consistency matching at the interface. Based on the interface topology, an acoustic-structure coupling interface and a fluid load interface are established respectively, and the acoustic-structure coupling interface and the fluid load interface coincide in geometric position but are logically independent of each other; wherein, the acoustic-structure coupling interface is used to establish the coupling relationship between sound pressure and structural displacement, so as to introduce the fluid-added mass generated by the acoustic fluid unit mesh into the system matrix. The transient fluid load acting on the blade structure surface is obtained based on the second fluid domain mesh, and the transient fluid load is mapped to the blade structure surface as an external excitation force through the fluid load interface; Within a unidirectional coupling framework, based on the system mass matrix including the fluid-added mass and the external excitation force, the transient dynamic control equations are constructed and solved to obtain the transient dynamic response of the blade structure in the underwater environment.

[0005] According to the blade fluid-structure interaction analysis method based on acoustic element adaptation provided by the present invention, the step of converting the first fluid domain mesh into an acoustic fluid element mesh with only pressure degree of freedom includes: selecting fluid elements in the first fluid domain from the geometric model based on component identification information using a parameterized script; The set of fluid elements to be converted in the first fluid domain is automatically determined according to the coupling solution requirements, and the set of fluid elements is adaptively converted into acoustic fluid elements. Modify the unit type identifier of the fluid unit in the first fluid domain to a preset acoustic fluid unit type; The degree-of-freedom set of the acoustic fluid unit type is limited to include only pressure degree of freedom, and the original displacement and velocity degrees of freedom of the fluid unit are deleted or masked.

[0006] According to the blade fluid-structure interaction analysis method based on acoustic unit adaptation provided by the present invention, before modifying the unit type identifier of the fluid unit in the first fluid domain to a preset acoustic fluid unit type, the method further includes: reading the original material identifier and unit number of the fluid unit. By using a parametric script to disable the solver's element shape check function based on the original material identifier and element number, the fluid element is converted into an acoustic fluid element, and the original material properties of the fluid element are mapped to the converted acoustic fluid element.

[0007] According to the blade fluid-structure interaction analysis method based on acoustic unit adaptation provided by the present invention, the establishment of the acoustic-structure interaction interface and the fluid load interface based on the interface topology includes: A topological contact pair is established between the outer surface of the blade structural domain and the inner surface of the first fluid domain, and the acoustic-structure coupling interface is constructed based on the topological contact pair; the acoustic-structure coupling interface is used to establish the coupling relationship between sound pressure and structural displacement, so as to introduce the fluid-added mass generated by the acoustic fluid unit mesh into the system matrix; A load receiving surface is independently constructed on the outer surface of the blade structure domain, and the fluid load interface is constructed based on the load receiving surface; the fluid load interface is used to transmit transient fluid loads obtained based on the final solution of the second fluid domain mesh.

[0008] According to the acoustic element-based adaptive blade fluid-structure interaction analysis method provided by the present invention, the step of calculating the nodal geometric deviation and load projection error at the interface between the acoustic fluid element mesh and the blade structure mesh based on the initial transient fluid load distribution and the blade structure mesh includes: Calculate the normal projection distance between corresponding nodes at the interface of the acoustic fluid element mesh and the blade structure mesh, and use it as the node geometric deviation; The difference between the projection value of the initial transient fluid load distribution on the blade structure grid and the projection value on the acoustic fluid element grid is calculated as the load projection error.

[0009] According to the blade fluid-structure interaction analysis method based on acoustic unit adaptation provided by the present invention, the step of constructing the interface mapping fidelity index based on the nodal geometric deviation and load projection error includes: The node geometric deviation and the load projection error are normalized respectively; The interface mapping fidelity index is obtained by weighted summation of the normalized node geometric deviation and the normalized load projection error.

[0010] According to the blade fluid-structure interaction analysis method based on acoustic element adaptation provided by the present invention, after adaptively converting the fluid elements in the first fluid domain mesh into an acoustic fluid element mesh with only pressure degrees of freedom, the method further includes: Zero-pressure boundary conditions or non-reflection boundary conditions are applied to the outer boundary of the first fluid domain to simulate an infinite water environment.

[0011] This invention also provides a blade fluid-structure interaction analysis system based on acoustic unit adaptation, comprising: The model building module is used to build a geometric model that includes a blade structural domain, a first fluid domain, and a second fluid domain, and to discretize the blade structural domain, the first fluid domain, and the second fluid domain to generate blade structural mesh, first fluid domain mesh, and second fluid domain mesh respectively. The conversion module is used to adaptively convert the fluid elements in the first fluid domain mesh into an acoustic fluid element mesh with only pressure degrees of freedom, according to the coupling solution requirements. The pre-solution module is used to perform transient flow field pre-solution based on the second fluid domain grid to obtain the initial transient fluid load distribution acting on the blade structure surface; The optimization module is used to calculate the node geometric deviation and load projection error of the acoustic fluid element mesh and the blade structure mesh at the interface based on the initial transient fluid load distribution and the blade structure mesh. It constructs an interface mapping fidelity index based on the node geometric deviation and load projection error. When the index is lower than a preset threshold, it performs adaptive mesh refinement on the local area of ​​the error concentration, triggering the pre-solution module to perform iterative calculation with itself until the index reaches or exceeds the preset threshold. An interface construction module is used to establish an acoustic-structure coupling interface and a fluid load interface based on the interface topology, wherein the acoustic-structure coupling interface and the fluid load interface coincide in geometric position but are logically independent of each other; The mapping module is used to obtain the transient fluid load acting on the blade structure surface based on the final solution of the second fluid domain mesh, and to map the transient fluid load to the blade structure surface as an external excitation force through the fluid load interface; The solver module is used to construct and solve the transient dynamic control equations based on the system mass matrix including the fluid-added mass and the external excitation force within a unidirectional coupling framework, thereby obtaining the transient dynamic response of the blade structure in the underwater environment.

[0012] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the blade fluid-structure interaction analysis method based on acoustic unit adaptation as described in any of the preceding claims.

[0013] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the blade fluid-structure interaction analysis method based on acoustic unit adaptation as described above.

[0014] This invention provides a blade fluid-structure interaction analysis method, system, electronic device, and storage medium based on acoustic element adaptive fluid-structure interaction. It constructs a geometric model comprising a blade structural domain, a first fluid domain, and a second fluid domain. The blade structural domain, the first fluid domain, and the second fluid domain are discretized to generate blade structural meshes, first fluid domain meshes, and second fluid domain meshes, respectively. The first fluid domain mesh is identified, and by modifying element attribute keywords, it is redefined as an acoustic fluid element with only pressure degrees of freedom. The acoustic fluid element shares the same interface topology with the blade structural mesh. Logically independent acoustic-structure interaction interfaces and fluid load interfaces are constructed on these interface topologies. The acoustic-structure interaction interfaces are used to establish the coupling relationship between sound pressure and structural displacement, thereby introducing a fluid load into the system matrix. The acoustic fluid unit generates additional mass; the fluid load interface is used to unidirectionally receive transient fluid loads calculated based on the second fluid domain mesh; the transient fluid loads are mapped to the blade structure surface through the fluid load interface as external excitation forces; simultaneously, a system mass matrix containing the fluid additional mass effect is constructed based on the acoustic-structure coupling interface so that the additional mass is synchronously coupled with the structural mode shape; under the unidirectional coupling framework, based on the assembled system mass matrix and the external excitation force, the transient dynamic control equations are constructed and solved to obtain the transient dynamic response of the blade structure in the underwater environment. This invention, while maintaining the high computational efficiency of unidirectional coupling, realizes the introduction of high-fidelity fluid additional mass effects that match the actual mode shape of the blade, solving the core contradiction in the prior art that it is difficult to balance computational efficiency and prediction accuracy. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the blade fluid-structure interaction analysis method based on acoustic unit adaptation provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of acoustic domain reconstruction and dual interface construction provided in an embodiment of the present invention; Figure 3 This is a flowchart of the interface mapping fidelity adaptive optimization provided in the embodiments of the present invention; Figure 4 This is a mode shape diagram of a hydrofoil blade provided in an embodiment of the present invention; Figure 5This is a comparison diagram of the transient dynamic response of the blades provided in the embodiments of the present invention; Figure 6 This is a functional structure diagram of the blade fluid-structure interaction analysis system based on acoustic unit adaptation provided in the embodiments of the present invention; Figure 7 This is a functional structure diagram of the electronic device provided in the embodiments of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0018] Figure 1 A flowchart of the blade fluid-structure interaction analysis method based on acoustic unit adaptation provided in the embodiments of the present invention is shown below. Figure 1 As shown, the blade fluid-structure interaction analysis method based on acoustic unit adaptation provided in this embodiment of the invention includes: Step 101: Construct a geometric model including a blade structure domain, a first fluid domain, and a second fluid domain. Discretize the blade structure domain, the first fluid domain, and the second fluid domain to generate blade structure mesh, first fluid domain mesh, and second fluid domain mesh, respectively. In this embodiment of the invention, taking the NACA0009 blade as an example, a three-dimensional geometric model is constructed, which includes the blade entity (structural domain) and the surrounding first fluid domain for extracting additional mass and the second fluid domain for solving the flow field.

[0019] Step 102: Based on the coupling solution requirements, the fluid elements in the first fluid domain mesh are adaptively converted into acoustic fluid element meshes with only pressure degrees of freedom; the transient flow field pre-solution is performed based on the second fluid domain mesh to obtain the initial transient fluid load distribution acting on the blade structure surface; Step 103: Based on the initial transient fluid load distribution and the blade structure mesh, calculate the node geometric deviation and load projection error at the interface between the acoustic fluid element mesh and the blade structure mesh. Construct an interface mapping fidelity index based on the node geometric deviation and load projection error. When the index is lower than a preset threshold, perform adaptive mesh refinement on the local area of ​​the error concentration, triggering the pre-solution module to perform iterative calculations with itself until the index reaches or exceeds the preset threshold. In this embodiment of the invention, logical independence means that although two sets of interfaces are constructed at the same physical interface location and spatially overlap, they are separated in terms of functional definition, data source, transmission direction, and solver processing mechanism. Specifically, the acoustic-structure coupling interface is used to establish the coupling relationship between sound pressure and structural displacement, generating an additional mass matrix from acoustic fluid elements in real time during the solution process; the fluid load interface is used to unidirectionally receive transient pressure data obtained from computational fluid dynamics (CFD) simulations based on the second fluid domain mesh, and generate external excitation forces acting on the structural surface through interpolation mapping. The two sets of interfaces work in parallel without interfering with each other, thus simultaneously accommodating the introduction of fluid inertial effects and the application of external fluid loads within the same model.

[0020] Step 104: Based on the second fluid domain mesh, the transient fluid load acting on the blade structure surface is finally obtained, and the transient fluid load is mapped to the blade structure surface as an external excitation force through the fluid load interface; Step 105: Under the unidirectional coupling framework, based on the system mass matrix including the fluid-added mass and the external excitation force, construct and solve the transient dynamic control equations to obtain the transient dynamic response of the blade structure in the underwater environment.

[0021] Traditional unidirectional fluid-structure interaction methods typically employ a dry modal analysis approach. This means that when solving the dynamic equations, the structure only includes its own mass matrix, completely ignoring the frequency shift effect of the fluid's added mass on the modal frequencies. While this simplification is computationally efficient, it fails to reflect the fundamental changes in the structure's inherent properties caused by the fluid environment. This leads to serious distortion risks in resonance prediction and transient response analysis, often overestimating the structure's natural frequencies and thus overlooking potential low-frequency resonance hazards.

[0022] The blade fluid-structure interaction analysis method based on acoustic element adaptation provided in this invention constructs a geometric model including a blade structural domain, a first fluid domain, and a second fluid domain. The blade structural domain, the first fluid domain, and the second fluid domain are discretized to generate blade structural meshes, first fluid domain meshes, and second fluid domain meshes, respectively. The first fluid domain mesh is identified, and by modifying the element attribute keywords, it is redefined as an acoustic fluid element with only pressure degrees of freedom. The acoustic fluid element shares the same interface topology with the blade structural mesh. Logically independent acoustic-structure interaction interfaces and fluid load interfaces are constructed on these interface topologies. The acoustic-structure interaction interfaces are used to establish the coupling relationship between sound pressure and structural displacement, thereby introducing the fluid load into the system matrix. The acoustic-fluid unit generates additional mass; the fluid load interface is used to receive transient fluid loads calculated from the external flow field in a one-way manner; the transient fluid loads are mapped to the blade structure surface through the fluid load interface as external excitation forces; simultaneously, a system mass matrix containing the fluid-added mass effect is constructed based on the acoustic-structure coupling interface so that the added mass is synchronously coupled with the structural mode shape; under the one-way coupling framework, based on the assembled system mass matrix and the external excitation force, the transient dynamic control equations are constructed and solved to obtain the transient dynamic response of the blade structure in the underwater environment. This embodiment of the invention, while maintaining the high computational efficiency of one-way coupling, realizes the introduction of high-fidelity fluid-added mass effects that match the actual mode shape of the blade, solving the core contradiction in the prior art where computational efficiency and prediction accuracy are difficult to balance.

[0023] Based on any of the above embodiments, the step of identifying the first fluid domain mesh and redefining the first fluid domain mesh as an acoustic fluid element with only pressure degrees of freedom by modifying the element attribute keywords includes: Step 201: Based on the component identification information, use a parameterized script to filter out all fluid units within the fluid domain from the geometric model; Step 202: Change the unit type identifier of all fluid units in the first fluid domain to the preset acoustic fluid unit type; Step 203: Lock the degree of freedom set of the acoustic fluid unit type to include only pressure degree of freedom, and remove the original displacement degree of freedom and velocity degree of freedom of the fluid unit, so that the fluid unit only has the ability to transmit sound pressure.

[0024] In this embodiment of the invention, after the model is imported into the structural dynamics solver, the initial first fluid domain mesh is typically identified by default as a solid element with displacement degrees of freedom, such as SOLID185. By inserting a parametric command snippet, APDLCommand Snippet, all elements within the first fluid domain are first identified based on the component name. Subsequently, a new acoustic element type ID (such as FLUID220) is defined using the ET command, and the critical option KEYOPT(1)=1 is set to disable displacement degrees of freedom (UX, UY, UZ), retaining only the pressure degree of freedom (PRES).

[0025] Based on any of the above embodiments, before changing the unit type identifier of all the selected fluid units in the first fluid domain to a preset acoustic fluid unit type, the method further includes: Step 301: Read the original material identifier and unit number of the fluid unit; Step 302: Using a parameterized script, disable the solver's element shape check function based on the original material identifier and element number of the fluid element, modify the element type identifier of the selected fluid element to the preset acoustic fluid element type, and map the original material properties of the fluid element to the modified acoustic fluid element.

[0026] In this embodiment of the invention, the solver's element shape checking function (SHPP, OFF) is disabled, and the EMODIF command is used to forcibly modify all element types in the first fluid domain to the newly defined acoustic elements. This operation successfully achieves in-situ reconstruction from structural elements to acoustic elements without changing the mesh geometry and topology.

[0027] Based on any of the above embodiments, constructing logically independent acoustic-structure coupling interfaces and fluid load interfaces on the interface topology includes: A topological contact pair is established between the outer surface of the blade structural domain and the inner surface of the first fluid domain, with the structural side designated as the target surface and the fluid side as the contact surface. Based on the topological contact pair, an acoustic-structure coupling interface is established to receive the coupling relationship between sound pressure and structural displacement, and to transmit the mutual feedback variables between sound pressure load and structural displacement. An independent load receiving surface is established on the outer surface of the blade structure domain, and a fluid load interface is established based on the load receiving surface. The fluid load interface and the acoustic-structure coupling interface are spatially coincident but logically independent.

[0028] like Figure 2 As shown, at the interface where the physical spaces overlap, this embodiment of the invention constructs two sets of interfaces that are completely decoupled in function: Acousto-structure coupling interface: Defined as the outer surface of the blade structural domain and the inner surface of the first fluid domain. By applying acoustic-structure coupling, the key fluid-structure coupling options of the contact element are activated. This interface is used to construct the coupling matrix [M_{added}] between fluid acoustic pressure and structural displacement during the solution process, and the interaction force vectors in its coupling equations. The calculation formula satisfies: Where [N] is the shape function matrix of the structural unit, {n} is the normal vector of the fluid-solid interface, P is the sound pressure of the fluid unit node, and S is the coupling surface area.

[0029] The fluid load interface is used to generate an external excitation force vector. Their mapping relationship satisfies: in, P cfd, i (t) represents time. t Pressure at nearby fluid mesh nodes, A i For the corresponding structural unit's force-bearing area, { n i} represents the surface normal vector of the structure. ω i These are the spatial interpolation weighting coefficients.

[0030] Based on any of the above embodiments, after redefining the first fluid domain grid as an acoustic fluid element with only pressure degrees of freedom, it further includes: Step 401: Execute the attribute deletion command to clear the original attributes under the material identifier corresponding to the acoustic fluid unit; Step 402: After clearing the original properties, the material identifier is reassigned with pure fluid density and sound velocity parameters to obtain the property-redefined acoustic fluid unit. Step 403: Redefine the acoustic fluid unit based on the properties to generate additional mass.

[0031] Based on any of the above embodiments, after redefining the first fluid domain grid as an acoustic fluid element with only pressure degrees of freedom, it further includes: Step 501: Apply zero-pressure boundary conditions or non-reflection boundary conditions to the outermost surface of the first fluid domain to simulate an infinite water boundary; Step 502: Construct and solve the transient dynamic control equations under the boundary of the infinite water area.

[0032] In this embodiment of the invention, boundary conditions and fluid properties are applied to define the density and sound velocity properties of the acoustic fluid element. Zero-pressure or non-reflective boundary conditions are applied to the outermost surface of the first fluid domain to simulate the stiffness or damping characteristics of the water boundary. After reconstructing the element type, the material fluid density (DENS, e.g., 1000 kg / m^3) and sound velocity (SONC, e.g., 1486 m / s) parameters are reassigned. Furthermore, a zero-pressure boundary condition (Pressure = 0) is applied to the outermost surface of the first fluid domain to construct an acoustic boundary compatible with a symmetric solver, simulating an infinite water environment.

[0033] Based on any of the above embodiments, before establishing a topological contact pair between the outer surface of the blade structural domain and the inner surface of the first fluid domain, the method further includes: Step 601: Define the interface mapping fidelity index, which is calculated based on the weighted average of the interface node geometric deviation and the pressure load integral error. Step 602: Determine whether the current indicator is greater than a preset threshold; Step 603: If the error is less than the preset threshold, identify the local area of ​​error concentration and use local mesh refinement technology to densify the high-pressure gradient region cells. Step 604: Repeat the above calculation and judgment process until the index is greater than the preset threshold. Then lock the topology of the first fluid domain as the geometric basis for constructing the acoustic-structure coupling interface and the fluid load interface.

[0034] like Figure 3 As shown, an interface mapping fidelity index γ is defined, which is calculated based on the weighted average of the interface node geometric deviation and the pressure load integral error; it is then determined whether the current γ is greater than a preset threshold γ. th =99%; if γ < γ th If the local area of ​​error concentration is identified, the high-pressure gradient region cell is densified using local mesh refinement technology; the above calculation and judgment process is repeated until γ > γth, and then the topology of the equivalent first fluid domain is locked for subsequent dual interface construction.

[0035] The calculation model for the mapping fidelity index γ is as follows: In the formula: The geometric deviation is the normal projection distance from the i-th node on the acoustic-solid interface to the actual blade geometric surface. This refers to the characteristic length of the leaf blade, i.e., the chord length. and These are the pressure distributions of the second flow field (i.e., the second fluid domain) and the target acoustic domain (i.e., the first fluid domain), respectively. , These are the weighting coefficients. + =1, for example, take =0.4, =0.6, emphasizing the accuracy of load transfer.

[0036] Based on the second fluid domain mesh, the unsteady pressure data on the blade surface calculated by the CFD solver is imported into the structural analysis module and mapped to the blade structure nodes through the established fluid load interface. Simultaneously, the solver automatically calculates and assembles the added mass matrix [M_{added}] generated by the acoustic-fluid elements using the "acoustic-structure interaction interface," and superimposes it into the total system mass matrix. The mode shapes corresponding to the first-order bending mode of the blade structure are as follows: Figure 4 As shown.

[0037] Within a unidirectional coupling framework, based on the assembled system matrix and the mapped fluid loads, transient dynamic control equations containing fluid load terms and additional mass matrix terms are constructed: in,[ M s ]、[ C s ]、[ K s [These represent the mass, damping, and stiffness matrices of the blade structure itself;] The equivalent additional mass matrix generated by the acoustic fluid unit; This is the fluid stiffness matrix (which is usually ignored or simplified under the incompressibility assumption); The transient fluid load, which varies with time, is obtained through mapping. The solver is configured as an asymmetric solver to handle the asymmetric acoustic-structure interaction matrix. The above equations are integrated in the time domain to obtain the blade displacement. ,speed and acceleration response .

[0038] The transient dynamic control equations are solved using a finite element solver, and the transient dynamic response of the underwater blade structure is calculated and output.

[0039] For the cleaned symmetric system matrix, a symmetric matrix eigenvalue solver or a sparse matrix direct solver is used to integrate and solve the above equations in the time domain. The final output is the displacement, velocity, and acceleration response of the blade under underwater flow field excitation.

[0040] like Figure 5As shown, the calculation results of the traditional unidirectional coupling method (ignoring the added mass) and the method provided by this invention are compared. It can be seen that the traditional method, due to ignoring the added mass of the fluid, predicts a higher resonant frequency, resulting in a significant deviation between the response amplitude at certain specific rotational speeds and the actual situation, and failing to accurately capture the low-frequency resonance peak. In contrast, the response curve calculated by the method provided by this invention not only exhibits a frequency shift consistent with physical laws, but also has a response amplitude closer to the experimental value. This proves that the method of this application, through parameterized unit reconstruction and dual-interface decoupling technology, successfully introduces accurate fluid inertial effects within the unidirectional coupling framework, effectively solving the frequency prediction distortion problem caused by model simplification in the traditional method, and providing a more reliable basis for the vibration-resistant design of underwater structures.

[0041] The blade fluid-structure interaction analysis method based on acoustic unit adaptation provided in this invention constructs an equivalent acoustic-fluid domain through parameterized unit reconstruction technology; it proposes an interface iterative optimization mechanism based on mapping fidelity, defining a load transfer matching index γ. The interface topology is locked only when γ exceeds a preset high-fidelity threshold, such as 99%; otherwise, a local refinement algorithm is used to iteratively correct the interface mesh. Furthermore, based on the optimized interface, a logically decoupled dual-interface mechanism is adopted to simultaneously realize the unidirectional transfer of unsteady fluid loads and the combination of the acoustic-structure interaction mass matrix at the physical interface. Based on this system, fluid inertial effects are integrated into the unidirectional coupling calculation framework to construct and solve the dynamic control equations containing fluid load terms and additional mass terms. This application can achieve high-fidelity simulation including accurate additional mass effects while maintaining high computational efficiency of unidirectional coupling, effectively solving the problem of distorted prediction of structural dynamic characteristics caused by neglecting water inertia in existing methods.

[0042] The following describes the blade fluid-structure interaction analysis system based on acoustic unit adaptation provided by the present invention. The blade fluid-structure interaction analysis system based on acoustic unit adaptation described below can be referred to in correspondence with the blade fluid-structure interaction analysis method based on acoustic unit adaptation described above.

[0043] Figure 6 The functional structure diagram of the blade fluid-structure interaction analysis system based on acoustic unit adaptation provided in the embodiments of the present invention is as follows: Figure 6 As shown, the blade fluid-structure interaction analysis system based on acoustic unit adaptation provided in this embodiment of the invention includes: The model building module 601 is used to build a geometric model including a blade structure domain, a first fluid domain and a second fluid domain, and to discretize the blade structure domain, the first fluid domain and the second fluid domain respectively to generate a blade structure mesh, a first fluid domain mesh and a second fluid domain mesh. The conversion module 602 is used to adaptively convert the fluid elements in the first fluid domain mesh into an acoustic fluid element mesh with only pressure degrees of freedom according to the coupling solution requirements. The pre-solution module is used to perform transient flow field pre-solution based on the second fluid domain grid to obtain the initial transient fluid load distribution acting on the blade structure surface; The optimization module 603 is used to calculate the node geometric deviation and load projection error of the acoustic fluid element mesh and the blade structure mesh at the interface based on the initial transient fluid load distribution and the blade structure mesh. It constructs an interface mapping fidelity index based on the node geometric deviation and load projection error. When the index is lower than a preset threshold, it performs adaptive mesh refinement on the local area of ​​the error concentration, triggering the pre-solution module to perform iterative calculation with itself until the index reaches or exceeds the preset threshold. The interface construction module 604 is used to establish an acoustic-structure coupling interface and a fluid load interface based on the interface topology, wherein the acoustic-structure coupling interface and the fluid load interface coincide in geometric position but are logically independent of each other. The mapping module 605 is used to obtain the transient fluid load acting on the blade structure surface based on the final solution of the second fluid domain mesh, and to map the transient fluid load to the blade structure surface as an external excitation force through the fluid load interface. The solver module 606 is used to construct and solve the transient dynamic control equations based on the system mass matrix including the fluid-added mass and the external excitation force under a unidirectional coupling framework, so as to obtain the transient dynamic response of the blade structure in the underwater environment.

[0044] The blade fluid-structure interaction analysis system based on acoustic element adaptation provided in this invention constructs a geometric model comprising a blade structural domain, a first fluid domain, and a second fluid domain. The system discretizes these domains to generate blade structural meshes, first fluid domain meshes, and second fluid domain meshes. The first fluid domain mesh is identified and redefined as an acoustic fluid element with only pressure degrees of freedom by modifying element attribute keywords. The acoustic fluid element shares the same interface topology with the blade structural mesh. Logically independent acoustic-structure interaction interfaces and fluid load interfaces are constructed on these interface topologies. The acoustic-structure interaction interfaces are used to establish the coupling relationship between sound pressure and structural displacement, thereby introducing the acoustic fluid load into the system matrix. The unit generates additional mass; the fluid load interface is used to unidirectionally receive transient fluid loads obtained based on the second fluid domain mesh calculation; the transient fluid loads are mapped to the blade structure surface through the fluid load interface as external excitation forces; simultaneously, a system mass matrix containing the fluid additional mass effect is constructed based on the acoustic-structure coupling interface so that the additional mass is synchronously coupled with the structural mode shape; under the unidirectional coupling framework, based on the assembled system mass matrix and the external excitation force, the transient dynamic control equations are constructed and solved to obtain the transient dynamic response of the blade structure in the underwater environment. This embodiment of the invention, while maintaining the high computational efficiency of unidirectional coupling, realizes the introduction of high-fidelity fluid additional mass effects that match the actual mode shape of the blade, solving the core contradiction in the prior art that it is difficult to balance computational efficiency and prediction accuracy.

[0045] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730, and a communication bus 740. The processor 710, communication interface 720, and memory 730 communicate with each other via the communication bus 740. The memory 730 includes computer programs, an operating system, and acquired data. The processor 710 can call logical instructions in the memory 730 to execute a blade fluid-structure interaction analysis method based on acoustic element adaptation. This method includes: constructing a geometric model containing a blade structural domain, a first fluid domain, and a second fluid domain; discretizing the blade structural domain, the first fluid domain, and the second fluid domain to generate blade structural meshes, first fluid domain meshes, and second fluid domain meshes; identifying the first fluid domain mesh; and redefining the first fluid domain mesh as an acoustic fluid element with only pressure degrees of freedom by modifying element attribute keywords; the acoustic fluid element and the blade structural mesh share the same interface topology; and constructing a logical... The system comprises an independent acoustic-structure interaction (AS / S) interface and a fluid load interface. The AS / S interface is used to establish the coupling relationship between sound pressure and structural displacement, so as to introduce additional mass generated by the acoustic fluid unit into the system matrix. The fluid load interface is used to unidirectionally receive transient fluid loads calculated based on the second fluid domain grid. The transient fluid loads are mapped to the blade structure surface through the fluid load interface as external excitation forces. At the same time, a system mass matrix containing the fluid additional mass effect is constructed based on the AS / S interface so that the additional mass is synchronously coupled with the structural mode shape. Under the unidirectional coupling framework, based on the assembled system mass matrix and the external excitation force, the transient dynamic control equations are constructed and solved to obtain the transient dynamic response of the blade structure in the underwater environment.

[0046] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to related technologies, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0047] On the other hand, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the blade fluid-structure interaction analysis method based on acoustic element adaptation provided by the above methods. This method includes: constructing a geometric model comprising a blade structural domain and a fluid domain; discretizing the structural domain and the fluid domain respectively to generate a structural mesh and a fluid mesh; identifying the fluid mesh and redefining it as an acoustic fluid element with only pressure degrees of freedom by modifying element attribute keywords; the acoustic fluid element and the structural mesh sharing the same interface topology; constructing a geometric model comprising a blade structural domain, a first fluid domain, and a second fluid domain on the interface topology; discretizing the blade structural domain, the first fluid domain, and the second fluid domain respectively to generate a blade structural mesh, a first fluid domain mesh, and a second fluid domain mesh; identifying the first fluid domain mesh and redefining it as an acoustic fluid element with only pressure degrees of freedom by modifying element attribute keywords. The first fluid domain mesh is redefined as an acoustic fluid element with only pressure degrees of freedom. The acoustic fluid element shares the same interface topology with the blade structure mesh. On the interface topology, a logically independent acoustic-structure coupling interface and a fluid load interface are constructed. The acoustic-structure coupling interface is used to establish the coupling relationship between sound pressure and structural displacement to introduce additional mass generated by the acoustic fluid element into the system matrix. The fluid load interface is used to unidirectionally receive transient fluid loads calculated based on the second fluid domain mesh. The transient fluid loads are mapped to the blade structure surface through the fluid load interface as external excitation forces. Simultaneously, a system mass matrix containing the fluid additional mass effect is constructed based on the acoustic-structure coupling interface to synchronously couple the additional mass with the structural mode shape. Under the unidirectional coupling framework, based on the assembled system mass matrix and the external excitation force, the transient dynamic control equations are constructed and solved to obtain the transient dynamic response of the blade structure in the underwater environment.

[0048] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0049] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A blade fluid-structure interaction analysis method based on acoustic unit adaptation, characterized in that, include: A geometric model containing a blade structural domain, a first fluid domain, and a second fluid domain is constructed, and the blade structural domain, the first fluid domain, and the second fluid domain are discretized to generate blade structural mesh, first fluid domain mesh, and second fluid domain mesh respectively. Based on the coupling solution requirements, the fluid elements in the first fluid domain mesh are adaptively converted into an acoustic fluid element mesh with only pressure degrees of freedom; Based on the second fluid domain mesh, perform transient flow field pre-solution to obtain the initial transient fluid load distribution acting on the blade structure surface; Based on the initial transient fluid load distribution and the blade structure mesh, the nodal geometric deviation and load projection error of the acoustic fluid element mesh and the blade structure mesh at the interface are calculated, and the interface mapping fidelity index is constructed based on the nodal geometric deviation and load projection error. When the interface mapping fidelity index is lower than the preset threshold, adaptive mesh refinement is performed on the local area of ​​the error concentration, and the calculation and refinement process is repeated until the interface mapping fidelity index reaches or exceeds the preset threshold, so that the acoustic fluid element mesh and the blade structure mesh can adaptively achieve topological consistency matching at the interface. Based on the interface topology, an acoustic-structure coupling interface and a fluid load interface are established respectively, and the acoustic-structure coupling interface and the fluid load interface coincide in geometric position but are logically independent of each other; wherein, the acoustic-structure coupling interface is used to establish the coupling relationship between sound pressure and structural displacement, so as to introduce the fluid-added mass generated by the acoustic fluid unit mesh into the system matrix. The transient fluid load acting on the blade structure surface is obtained based on the second fluid domain mesh, and the transient fluid load is mapped to the blade structure surface as an external excitation force through the fluid load interface; Within a unidirectional coupling framework, based on the system mass matrix including the fluid-added mass and the external excitation force, the transient dynamic control equations are constructed and solved to obtain the transient dynamic response of the blade structure in the underwater environment.

2. The blade fluid-structure interaction analysis method based on acoustic unit adaptation according to claim 1, characterized in that, The step of converting the first fluid domain mesh into an acoustic fluid element mesh with only pressure degrees of freedom includes: using a parametric script to filter out fluid elements within the first fluid domain from the geometric model based on component identification information; The set of fluid elements to be converted in the first fluid domain is automatically determined according to the coupling solution requirements, and the set of fluid elements is adaptively converted into acoustic fluid elements. Modify the unit type identifier of the fluid unit in the first fluid domain to a preset acoustic fluid unit type; The degree-of-freedom set of the acoustic fluid unit type is limited to include only pressure degree of freedom, and the original displacement and velocity degrees of freedom of the fluid unit are deleted or masked.

3. The blade fluid-structure interaction analysis method based on acoustic unit adaptation according to claim 2, characterized in that, Before modifying the unit type identifier of the fluid unit in the first fluid domain to a preset acoustic fluid unit type, the method further includes: reading the original material identifier and unit number of the fluid unit. By using a parametric script to disable the solver's element shape check function based on the original material identifier and element number, the fluid element is converted into an acoustic fluid element, and the original material properties of the fluid element are mapped to the converted acoustic fluid element.

4. The blade fluid-structure interaction analysis method based on acoustic unit adaptation according to claim 1, characterized in that, The establishment of the acoustic-structure coupling interface and the fluid load interface based on the interface topology includes: A topological contact pair is established between the outer surface of the blade structural domain and the inner surface of the first fluid domain, and the acoustic-structure coupling interface is constructed based on the topological contact pair; the acoustic-structure coupling interface is used to establish the coupling relationship between sound pressure and structural displacement, so as to introduce the fluid-added mass generated by the acoustic fluid unit mesh into the system matrix; A load receiving surface is independently constructed on the outer surface of the blade structure domain, and the fluid load interface is constructed based on the load receiving surface; the fluid load interface is used to transmit transient fluid loads obtained based on the final solution of the second fluid domain mesh.

5. The blade fluid-structure interaction analysis method based on acoustic unit adaptation according to claim 1, characterized in that, The calculation of nodal geometric deviation and load projection error at the interface between the acoustic fluid element mesh and the blade structure mesh, based on the initial transient fluid load distribution and the blade structure mesh, includes: Calculate the normal projection distance between corresponding nodes at the interface of the acoustic fluid element mesh and the blade structure mesh, and use it as the node geometric deviation; The difference between the projection value of the initial transient fluid load distribution on the blade structure grid and the projection value on the acoustic fluid element grid is calculated as the load projection error.

6. The blade fluid-structure interaction analysis method based on acoustic unit adaptation according to claim 5, characterized in that, The step of constructing the interface mapping fidelity index based on the node geometric deviation and load projection error includes: The node geometric deviation and the load projection error are normalized respectively; The interface mapping fidelity index is obtained by weighted summation of the normalized node geometric deviation and the normalized load projection error.

7. The blade fluid-structure interaction analysis method based on acoustic unit adaptation according to claim 1, characterized in that, After adaptively converting the fluid elements in the first fluid domain mesh into an acoustic fluid element mesh with only pressure degrees of freedom, the method further includes: Zero-pressure boundary conditions or non-reflection boundary conditions are applied to the outer boundary of the first fluid domain to simulate an infinite water environment.

8. A blade fluid-structure interaction analysis system based on acoustic unit adaptation, characterized in that, include: The model building module is used to build a geometric model that includes a blade structural domain, a first fluid domain, and a second fluid domain, and to discretize the blade structural domain, the first fluid domain, and the second fluid domain to generate blade structural mesh, first fluid domain mesh, and second fluid domain mesh respectively. The conversion module is used to adaptively convert the fluid elements in the first fluid domain mesh into an acoustic fluid element mesh with only pressure degrees of freedom, according to the coupling solution requirements. The pre-solution module is used to perform transient flow field pre-solution based on the second fluid domain grid to obtain the initial transient fluid load distribution acting on the blade structure surface; The optimization module is used to calculate the node geometric deviation and load projection error of the acoustic fluid element mesh and the blade structure mesh at the interface based on the initial transient fluid load distribution and the blade structure mesh. It constructs an interface mapping fidelity index based on the node geometric deviation and load projection error. When the index is lower than a preset threshold, it performs adaptive mesh refinement on the local area of ​​the error concentration, triggering the pre-solution module to perform iterative calculation with itself until the index reaches or exceeds the preset threshold. An interface construction module is used to establish an acoustic-structure coupling interface and a fluid load interface based on the interface topology, wherein the acoustic-structure coupling interface and the fluid load interface coincide in geometric position but are logically independent of each other; The mapping module is used to obtain the transient fluid load acting on the blade structure surface based on the final solution of the second fluid domain mesh, and to map the transient fluid load to the blade structure surface as an external excitation force through the fluid load interface; The solver module is used to construct and solve the transient dynamic control equations based on the system mass matrix including the fluid-added mass and the external excitation force within a unidirectional coupling framework, thereby obtaining the transient dynamic response of the blade structure in the underwater environment.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the blade fluid-structure interaction analysis method based on acoustic unit adaptation as described in any one of claims 1 to 7.

10. A non-transitory readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the blade fluid-structure interaction analysis method based on acoustic unit adaptation as described in any one of claims 1 to 7.

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