Numerical analysis method and system for fluid-structure-acoustic coupling based on underwater vehicle

Abstract

The application discloses a kind of fluid-solid acoustic coupling numerical analysis method and system based on underwater vehicle, its method includes: by finite volume method and the first parameter of the first time step of underwater vehicle carries out fluid calculation, obtains the first fluid calculation result of underwater vehicle;By modal superposition method, first parameter and the first flow field force in first fluid calculation result carry out solid calculation, obtain the first solid calculation result of underwater vehicle;First control point information of first solid calculation result, finite volume method and the second parameter of the second time step of underwater vehicle carry out fluid calculation, obtain the second fluid calculation result of underwater vehicle;Iterate in turn until the N fluid calculation result of last time step is obtained;The N fluid calculation result is substituted into acoustic pressure wave equation, obtains the forecast of far-field sound field.The application can numerically simulate the flow noise caused by underwater vehicle and fluid interaction, and has the advantages of accuracy, small cost and not affected by environment.

Description

Technical Field

[0001] This invention relates to the field of underwater vehicle numerical analysis technology, and in particular to a fluid-structure-acoustic coupling numerical analysis method and system based on underwater vehicles. Background Technology

[0002] In the development of underwater vehicles, fluid-structure-acoustic coupling (FSA) problems are widespread, namely the interaction between fluids and structures, which significantly affects the generation and propagation of sound. Accurate sound pressure calculation for underwater FSA problems requires the accurate and efficient handling of complex FSA effects. The complexity of FSA lies primarily in the complex aggregate shape of the underwater vehicle surface, the need to consider motion, and the occurrence of deformation. However, most current FSA methods struggle to efficiently capture fluid-structure boundaries and describe surface deformation. Furthermore, most FSA problems are difficult to analyze analytically, and traditional numerical simulations are inadequate for solving such problems. Therefore, developing theoretical calculation models and methods for shipboard FSA is of great significance. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a fluid-structure-acoustic coupling numerical analysis method and system based on underwater vehicles, which can accurately and quantitatively analyze the flow noise problem caused by the interaction between fluid and vehicle structure in different working environments of underwater vehicles, and has the advantages of low cost and insensitivity to environmental factors.

[0004] In a first aspect, embodiments of the present invention provide a fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle, the method comprising: Obtain parameters for multiple time steps of the underwater vehicle; Fluid calculations are performed using the finite volume method and the first parameters of the first time step of the underwater vehicle to obtain the first fluid calculation result. Solid calculations are then performed using the modal superposition method, the first parameters, and the first flow field force from the first fluid calculation result to obtain the first solid calculation result. Fluid calculations are then performed using the first control point information from the first solid calculation result, the finite volume method, and the second parameters of the second time step of the underwater vehicle to obtain the second fluid calculation result. Solid calculations are then performed using the second flow field force from the second fluid calculation result, the modal superposition method, and the second parameters to obtain the second solid calculation result. This process is iterated until the Nth fluid calculation result of the last time step of the underwater vehicle is obtained, where N represents a positive integer. Substituting the Nth fluid calculation result into the sound pressure wave equation, the prediction of the far-field sound field of the underwater vehicle is obtained.

[0005] The method according to embodiments of the present invention has at least the following beneficial effects: First, parameters of the underwater vehicle at multiple time steps are collected using a data acquisition device to analyze the fluid-solid interaction at each time step. Then, at the same time step, fluid calculations are performed using the finite volume method and the first parameter of the underwater vehicle. The flow field force in the fluid calculation results is also used for solid calculations at the same time step. Simultaneously, solid calculations are performed using the modal superposition method, the first parameter, and the flow field force. The control point information in the solid calculation results is also used for fluid calculations in the next time step. This iterative process of bidirectional coupling between fluid and solid is performed. The method of bidirectional coupling through numerical simulation and modal iteration has the advantages of low cost and insensitivity to environmental factors. It also provides an effective calculation approach and an accurate calculation method for fluid-solid-acoustic coupling of underwater vehicles. Finally, the Nth fluid calculation result is substituted into the sound pressure wave equation to calculate the prediction of the far-field sound field of the underwater vehicle. The pressure pulsation and flow noise caused by the micro-amplitude vibration of the solid are accurately calculated, enabling accurate prediction of the far-field sound field.

[0006] According to some embodiments of the present invention, the fluid computation is developed based on the finite volume method, and the fluid computation includes: numerically solving the flow field around the underwater vehicle structure using three-dimensional incompressible Navier-Stokes equations based on Eulerian grid discretization; wherein, the inviscid flux in the equations is selected using the ROE scheme and interpolated using the 3rd order MUSCL method with a Van Albada limiter, the viscous flux in the equations is discretized using the 2nd order central scheme, and the time propagation is performed using the LU-SGS scheme.

[0007] According to some embodiments of the present invention, the fluid calculation further includes turbulence simulation calculation, wherein the turbulence simulation calculation uses the LES method to perform turbulence simulation; wherein the model of the LES method adopts the Vreman eddy viscosity subgrid model.

[0008] According to some embodiments of the present invention, the calculation formula for the first flow field force includes:

[0009] in, Represents the flow field force. Indicates the time step, therefore the first flow field force up to the second... The formulas for calculating flow field forces are all the same. Indicates the wet noodle element number, and , Indicates the first The coordinates of the center point of each wet surface element Indicates the first The vibration mode at the center point of each wetted surface element Indicates the first The area of ​​each wet noodle unit, To act on the first The force vector distributed on the surface at the center point of each wet surface element.

[0010] According to some embodiments of the present invention, the solid-state calculation includes: The continuous structure of the underwater vehicle is converted into a system with multiple discrete degrees of freedom, and the dynamic equations of the system include:

[0011] in, , and Let these represent the mass matrix, damping matrix, and stiffness matrix of a dry structure in a vacuum, respectively. , and Let these represent the column vectors of displacement, velocity, and acceleration of discrete nodes in the system, respectively. Indicates a time step. This represents the dynamic force column vectors acting on the wetted surface of the structure by the flow field; The dynamic response characteristics of the system are solved by the modal superposition method, which extracts a finite number of modes; the mode shape displacement matrix corresponding to the finite number of modes includes:

[0012] in, express The column vector of modal displacements corresponding to the first mode. Represents a positive integer.

[0013] According to some embodiments of the present invention, solving the dynamic response characteristics of the system by the modal superposition method includes: The discrete nodal displacements of the structure in the system are calculated using the modal superposition method; the formulas for calculating the discrete nodal displacements include:

[0014] in, and Represent the generalized principal coordinate column vector and the first... Principal coordinate components of the step-by-step mode; The linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape of the floating structure nodes in the system are calculated using the modal superposition method. The calculation formulas for the linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape include:

[0015]

[0016] in, Indicates linear displacement. Indicates angular displacement. Indicates the mode shape of linear displacement. Indicates the mode shape of angular displacement; The principal coordinate motion equation of the system is calculated based on the discrete node displacements of the structure; the calculation formula for the principal coordinate motion equation includes:

[0017]

[0018] In the principal coordinate motion equation , and Let represent the generalized mass matrix, generalized damping matrix, and generalized stiffness matrix of the structural dry modes, respectively. All three matrices are diagonal matrices. This represents the force exerted by the acoustic medium flow field on the wet surface. Represents the force of the acoustic medium flow field on the wet surface The corresponding generalized hydrodynamic column vector, The first derivative of the generalized principal coordinate column vector is given by... The second derivative of the generalized principal coordinate column vector; The vibration velocity response is calculated based on the principal coordinate motion equation, the linear displacement, the linear displacement mode shape, the angular displacement, and the angular displacement mode shape; the calculation formula for the vibration velocity response includes:

[0019] in, The first derivative of linear displacement. The first derivative represents the mode shape of linear displacement. Indicates the first The first derivative of the principal coordinate component of the step mode.

[0020] According to some embodiments of the present invention, substituting the Nth fluid calculation result into the sound pressure wave equation to obtain a prediction of the far-field sound field of the underwater vehicle includes: The fluid pulsation pressure of the underwater vehicle is obtained from the Nth fluid calculation result; Substituting the fluid pulsating pressure into the sound pressure wave equation, the prediction of the far-field sound field of the underwater vehicle is obtained; the calculation formula of the sound pressure wave equation includes:

[0021] In the sound pressure wave equation Indicates pressure. , , Representing coordinate position, in the sound pressure wave equation This indicates the speed at which sound waves propagate in a medium.

[0022] Secondly, embodiments of the present invention provide a fluid-structure-acoustic coupling numerical analysis system based on an underwater vehicle, the fluid-structure-acoustic coupling numerical analysis system based on an underwater vehicle comprising: The parameter acquisition module is used to acquire parameters of the underwater vehicle at multiple time steps. The fluid-structure interaction module is used to perform fluid calculations using the finite volume method and the first parameters of the first time step of the underwater vehicle to obtain the first fluid calculation result of the underwater vehicle; to perform solid calculations using the modal superposition method, the first parameters, and the first flow field force in the first fluid calculation result to obtain the first solid calculation result of the underwater vehicle; to perform fluid calculations using the first control point information of the first solid calculation result, the finite volume method, and the second parameters of the second time step of the underwater vehicle to obtain the second fluid calculation result of the underwater vehicle; to perform solid calculations using the second flow field force of the second fluid calculation result, the modal superposition method, and the second parameters to obtain the second solid calculation result of the underwater vehicle; and to iterate sequentially until the Nth fluid calculation result of the last time step of the underwater vehicle is obtained, where N represents a positive integer; The fluid-structure-acoustic coupling module is used to substitute the Nth fluid calculation result into the sound pressure wave equation to obtain the prediction of the far-field sound field of the underwater vehicle.

[0023] Thirdly, embodiments of the present invention provide an electronic device including at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, the instructions being executed by the at least one control processor to enable the at least one control processor to perform the fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle as described in the first aspect.

[0024] Fourthly, embodiments of the present invention provide a computer storage medium storing computer-executable instructions for causing a computer to perform the fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle as described in the first aspect.

[0025] It should be noted that the beneficial effects of the second to fourth aspects of the present invention compared with the prior art are the same as the beneficial effects of the fluid-structure-acoustic coupling numerical analysis method based on underwater vehicles in the first aspect, and will not be described in detail here.

[0026] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart of a fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle, provided by an embodiment of the present invention; Figure 2 This is a flowchart of solid-state calculation provided in an embodiment of the present invention; Figure 3 This is a flowchart of solving the dynamic response characteristics of a system using the modal superposition method according to an embodiment of the present invention; Figure 4 This is a flowchart of a method for predicting the far-field acoustic field of an underwater vehicle, provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of a fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle according to an embodiment of the present invention; Figure 6 This is a structural diagram of a fluid-structure-acoustic coupling numerical analysis system based on an underwater vehicle, provided in an embodiment of the present invention. Figure 7 This is a structural diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] In the description of this invention, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0030] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0033] Reference Figure 1 In some embodiments of the present invention, a numerical analysis method for fluid-structure-acoustic coupling based on underwater vehicles is provided, including: Step S100: Obtain parameters for multiple time steps of the underwater vehicle.

[0034] Step S200: Perform fluid calculations using the finite volume method and the first parameters of the first time step of the underwater vehicle to obtain the first fluid calculation result of the underwater vehicle; perform solid calculations using the modal superposition method, the first parameters, and the first flow field force in the first fluid calculation result to obtain the first solid calculation result of the underwater vehicle; perform fluid calculations using the first control point information of the first solid calculation result, the finite volume method, and the second parameters of the second time step of the underwater vehicle to obtain the second fluid calculation result of the underwater vehicle; perform solid calculations using the second flow field force of the second fluid calculation result, the modal superposition method, and the second parameters to obtain the second solid calculation result of the underwater vehicle; iterate sequentially until the Nth fluid calculation result of the last time step of the underwater vehicle is obtained, where N represents a positive integer.

[0035] Step S300: Substitute the Nth fluid calculation result into the sound pressure wave equation to obtain the prediction of the far-field sound field of the underwater vehicle.

[0036] It should be noted that due to the complex shape and boundaries of underwater vehicle structures, the handling of boundary conditions in fluid dynamics calculations must be based on the structural shape, operational characteristics, and material properties. This method takes a typical underwater vehicle's conning tower structure as an example. Since the outer shell is in direct contact with seawater, its steel plates must be able to withstand enormous seawater pressure. The shell deformation is negligible compared to its dimensions. Furthermore, wall pressure fluctuations and structural deformation are not in phase. Therefore, for simplicity, the deformation of the conning tower surface is not considered in the fluid-structure interaction solution. This method also divides the computational domain into a sound source region and a propagation region. The calculation in step S200 is performed in the sound source region, and the calculation in step S300 is performed in the propagation region.

[0037] First, in step S100, the acquisition device collects parameters of the underwater vehicle at multiple time steps to analyze the fluid-solid interaction of the underwater vehicle at each time step. Then, in step S200, fluid calculations are performed at the same time step using the finite volume method and the first parameter of the underwater vehicle. The flow field force in the fluid calculation results is also used for solid calculations at the same time step. Simultaneously, solid calculations are performed using the modal superposition method, the first parameter, and the flow field force. The control point information in the solid calculation results will also be used for fluid calculations in the next time step. This iterative process of bidirectional coupling between fluid and solid is carried out. The method of bidirectional coupling through numerical simulation and modal iteration has the advantages of low cost and no influence from environmental factors. It also provides an effective calculation path and an accurate calculation method for fluid-solid-acoustic coupling of underwater vehicles. Finally, in step S300, the Nth fluid calculation result is substituted into the sound pressure wave equation to calculate the prediction of the far-field sound field of the underwater vehicle. The pressure pulsation and flow noise caused by the micro-amplitude vibration of the solid are accurately calculated, enabling accurate prediction of the far-field sound field.

[0038] In some embodiments of the present invention, the fluid computation is developed based on the finite volume method. The fluid computation includes: based on Eulerian grid discretization, numerically solving the flow field around the underwater vehicle structure using the three-dimensional incompressible Navier-Stokes equations; wherein, the inviscid flux in the equations is selected using the ROE scheme and interpolated using the Van Albada limiter through the third-order MUSCL method, the viscous flux in the equations is discretized using the second-order central scheme, and the time propagation is performed using the LU-SGS scheme.

[0039] It should be noted that fluid calculations require assigning flow parameters at the inlet boundary of the computational domain, while the outlet boundary is processed using extrapolation.

[0040] Fluid computation based on the finite volume method can improve the accuracy of fluid computation and enhance the accuracy of numerical analysis methods for fluid-structure-acoustic coupling of underwater vehicles.

[0041] In some embodiments of the present invention, the fluid calculation further includes turbulence simulation calculation, which uses the LES method to perform turbulence simulation; wherein the model of the LES method adopts the Vreman eddy viscosity subgrid model.

[0042] It should be noted that, in order to simulate turbulent flow, the computational domain must be large enough to encompass the largest eddies in the turbulent motion, while the computational grid must be small enough to resolve the motion of the smallest eddies. However, given current computing capabilities, the smallest usable computational grid scale is still much larger than the scale of the smallest eddy. Therefore, currently, we must abandon the simulation of eddy motion across the entire scale range and instead directly calculate the turbulent motion larger than the grid scale using the Navier-Stokes equations. The influence of small-scale eddies on large-scale motion is simulated by establishing a model, thus forming the current Large Eddy Simulation (LES) method.

[0043] The basic idea of ​​the LES method can be summarized as follows: use the instantaneous Navier-Stokes equations to directly simulate large-scale eddies in turbulence, without directly simulating small-scale eddies. The influence of small eddies on large eddies is considered through an approximate model, which can simulate relatively accurate calculation results and ensure the accuracy of fluid calculations.

[0044] In some embodiments of the present invention, the calculation formula for the first flow field force includes:

[0045] in, Represents the flow field force. Indicates the time step, therefore the first flow field force up to the second... The formulas for calculating flow field forces are all the same. Indicates the wet noodle element number, and , Indicates the first The coordinates of the center point of each wet surface element Indicates the first The vibration mode at the center point of each wetted surface element Indicates the first The area of ​​each wet noodle unit, To act on the first The force vector distributed on the surface at the center point of each wet surface element.

[0046] It should be noted that the fluid force in the wet mode can be transformed into a surface-distributed force (considering both normal and tangential components) at the center point of each wet surface element. The sign of the surface-distributed force is determined by the direction of the force acting on the structure. For example, if the force acting on the structure by the fluid has a component along the positive x-axis, it is positive; otherwise, it is negative. The surface-distributed force is a force per unit area, equivalent to pressure.

[0047] By calculating the first to Nth flow field forces using wetted surface elements, the fluid interaction of the flow field forces on the structure under wetted modes can be fully considered. By accurately calculating the first to Nth flow field forces, the fluid-structure interaction can be accurately simulated, thereby accurately and quantitatively analyzing the flow noise caused by the interaction between the fluid and the vehicle structure in different working environments of underwater vehicles.

[0048] Reference Figure 2 In some embodiments of the present invention, solid-state computing includes: Step S210: Convert the continuous structure of the underwater vehicle into a system with multiple discrete degrees of freedom. The dynamic equations of the system include:

[0049] in, , and Let these represent the mass matrix, damping matrix, and stiffness matrix of a dry structure in a vacuum, respectively. , and Let these represent the column vectors of displacement, velocity, and acceleration of discrete nodes in the system, respectively. Indicates a time step. This represents the dynamic force column vector of the flow field acting on the wetted surface of the structure.

[0050] Step S220: Solve the dynamic response characteristics of the system using the modal superposition method. The modal superposition method extracts a finite number of modes. The mode shape displacement matrix corresponding to the finite number of modes includes:

[0051] in, express The column vector of modal displacements corresponding to the first mode. Represents a positive integer.

[0052] It should be noted that in solid-state calculations, underwater vehicles are treated as exhibiting minute vibrations of their conning structure. The flow field excitation force on the wetted surface of the structure can be considered as an external excitation force acting on the structure. When the structure undergoes minute linear vibrations, the continuous structure is treated as a system with a finite number of discrete degrees of freedom.

[0053] The continuous structure of the underwater vehicle is transformed into a system with multiple discrete degrees of freedom. In this system, the forces exerted by the flow field on the dry structure can be accurately analyzed through the system's dynamic equations. Then, the dynamic response characteristics of the system are solved by the modal superposition method. The characteristics of fluid-solid interaction are calculated through simulation numerical calculation, which facilitates accurate fluid-structure interaction and accurate fluid-structure-acoustic interaction calculation.

[0054] Reference Figure 3 In some embodiments of the present invention, the dynamic response characteristics of the system are solved by the modal superposition method, including: Step S221: Calculate the discrete nodal displacements of the structure in the system using the modal superposition method; the calculation formulas for the discrete nodal displacements include:

[0055] in, and Represent the generalized principal coordinate column vector and the first... The principal coordinate components of the step mode.

[0056] Step S222: Calculate the linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape of the floating structure nodes in the system using the modal superposition method. The calculation formulas for the linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape include:

[0057]

[0058] in, Indicates linear displacement. Indicates angular displacement. Indicates the mode shape of linear displacement. This indicates the angular displacement mode shape.

[0059] Step S223: Calculate the principal coordinate motion equation of the system based on the discrete node displacements of the structure; the calculation formula for the principal coordinate motion equation includes:

[0060]

[0061] In the principal coordinate motion equation , and Let represent the generalized mass matrix, generalized damping matrix, and generalized stiffness matrix of the structural dry modes, respectively. All three matrices are diagonal matrices. This represents the force exerted by the acoustic medium flow field on the wet surface. Represents the force of the acoustic medium flow field on the wet surface The corresponding generalized hydrodynamic column vector, The first derivative of the generalized principal coordinate column vector is given by... It represents the second derivative of the generalized principal coordinate column vector.

[0062] Step S224: Calculate the vibration velocity response based on the principal coordinate motion equations, linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape; the calculation formula for the vibration velocity response includes:

[0063] in, The first derivative of linear displacement. The first derivative represents the mode shape of linear displacement. Indicates the first The first derivative of the principal coordinate component of the step mode.

[0064] It should be noted that the modal superposition method uses the vibration modes obtained from modal analysis to perform coordinate transformation and decoupling on the vibration response equation. This transforms the solution of a multi-degree-of-freedom system in the physical coordinate system into the solution of multiple single-degree-of-freedom systems in the modal coordinate system. The responses in each modal coordinate system are obtained separately, and then combined to obtain the response of the multi-degree-of-freedom system in the real physical coordinate system.

[0065] Simulation using the modal superposition method preserves specific modal vectors, and the resulting equations of motion can approximately reflect the main characteristics of the original system. This method is suitable for approximate modeling of active control structures with complex shapes and facilitates dynamic characteristic analysis.

[0066] Reference Figure 4 In some embodiments of the present invention, the calculation result of the Nth fluid is substituted into the sound pressure wave equation to obtain a prediction of the far-field sound field of the underwater vehicle, including: Step S301: Obtain the fluid pulsation pressure of the underwater vehicle through the Nth fluid calculation result; Step S302: Substitute the fluctuating fluid pressure into the sound pressure wave equation to obtain the prediction of the far-field sound field of the underwater vehicle; the calculation formula of the sound pressure wave equation includes:

[0067] In the sound pressure wave equation Indicates pressure. , , Representing coordinate position, in the sound pressure wave equation This indicates the speed at which sound waves propagate in a medium.

[0068] It should be noted that the sound pressure wave equation can be solved using the method of separation of variables to obtain its effective sound pressure, and thus ultimately obtain the sound pressure level in the sound source region and the propagation region.

[0069] The flow field in the sound source region was accurately solved by the Nth flow field force after fluid-structure interaction. Then, the fluid pulsating pressure was calculated to provide mature and accurate data support for the prediction of the subsequent far-field sound field. Finally, the far-field sound field was accurately predicted by the sound pressure wave equation.

[0070] Reference Figure 5To facilitate understanding by those skilled in the art, a specific embodiment of the present invention provides a numerical analysis method for fluid-structure-acoustic coupling based on underwater vehicles, comprising: Step 1: Fluid Calculation.

[0071] The fluid computation is developed based on the finite volume method. The computation includes: numerically solving the flow field around the underwater vehicle structure using three-dimensional incompressible Navier-Stokes equations based on Eulerian grid discretization; specifically, the inviscid flux in the equations uses the ROE scheme and is interpolated using a third-order MUSCL method with a Van Albada limiter; the viscous flux in the equations is discretized using a second-order central scheme, and time propagation is performed using the LU-SGS scheme. Fluid computation requires assigning inflow parameters at the inlet boundary of the computational domain, and extrapolation is used at the outlet boundary. The fluid computation also includes turbulence simulation, which uses the LES method; specifically, the LES method uses the Vreman eddy viscosity subgrid model.

[0072] Step 1: Solid Calculations.

[0073] Solid-state computation includes converting the continuous structure of an underwater vehicle into a system with multiple discrete degrees of freedom. The dynamic equations of the system include:

[0074] in, , and Let these represent the mass matrix, damping matrix, and stiffness matrix of a dry structure in a vacuum, respectively. , and Let these represent the column vectors of displacement, velocity, and acceleration of discrete nodes in the system, respectively. Indicates a time step. This represents the dynamic force column vector of the flow field acting on the wetted surface of the structure.

[0075] The dynamic response characteristics of the system are solved using the modal superposition method, which extracts a finite number of modes. The modal displacement matrices corresponding to the finite number of modes include:

[0076] in, express The column vector of modal displacements corresponding to the first mode. Represents a positive integer. The dynamic response characteristics of the system are solved using the modal superposition method, specifically including: The discrete nodal displacements of the system are calculated using the modal superposition method; the formulas for calculating the discrete nodal displacements include:

[0077] in, and Represent the generalized principal coordinate column vector and the first... The principal coordinate components of the step mode.

[0078] The linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape of the floating body structural nodes in the system are calculated using the modal superposition method. The calculation formulas for these parameters include:

[0079]

[0080] in, Indicates linear displacement. Indicates angular displacement. Indicates the mode shape of linear displacement. This indicates the angular displacement mode shape.

[0081] The principal coordinate motion equations of the system are calculated based on the discrete nodal displacements of the structure; the formulas for calculating the principal coordinate motion equations include:

[0082]

[0083] In the principal coordinate motion equation , and Let represent the generalized mass matrix, generalized damping matrix, and generalized stiffness matrix of the structural dry modes, respectively. All three matrices are diagonal matrices. This represents the force exerted by the acoustic medium flow field on the wet surface. Represents the force of the acoustic medium flow field on the wet surface The corresponding generalized hydrodynamic column vector, The first derivative of the generalized principal coordinate column vector is given by... It represents the second derivative of the generalized principal coordinate column vector.

[0084] The vibration velocity response is calculated based on the principal coordinate motion equations, linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape. The formulas for calculating the vibration velocity response include:

[0085] in, The first derivative of linear displacement. The first derivative represents the mode shape of linear displacement. Indicates the first The first derivative of the principal coordinate component of the step mode.

[0086] Step 3: Fluid-structure interaction calculation.

[0087] To simultaneously calculate the fluid and solid components, a weak coupling method is applied because the interaction between the deformation of the flexible structure and the unsteady flow field is highly sensitive. At each time step (N), control point information obtained from the structural calculation (the initial model of the flexible structure at N=0) is transferred to the flow field calculation in that step (N). The weak coupling method then allows the flow field forces obtained from the flow field calculation to be used in the structural calculation of the next time step (N+1), and this process is iterated continuously with each time step. Specifically: The underwater vehicle's first fluid calculation result is obtained by performing fluid calculations using the finite volume method and the first parameters of the first time step. The underwater vehicle's first solid calculation result is obtained by performing solid calculations using the modal superposition method, the first parameters, and the first flow field force from the first fluid calculation result. The underwater vehicle's second fluid calculation result is obtained by performing fluid calculations using the first control point information from the first solid calculation result, the finite volume method, and the second parameters of the second time step. The underwater vehicle's second solid calculation result is obtained by performing solid calculations using the second flow field force, the modal superposition method, and the second parameters from the second fluid calculation result. This process is iterated until the Nth fluid calculation result of the underwater vehicle's last time step is obtained, where N represents a positive integer.

[0088] Step 4: Fluid-structure-acoustic coupling calculation.

[0089] The fluid pulsation pressure of the underwater vehicle was obtained from the Nth fluid calculation result. Substituting the fluctuating fluid pressure into the sound pressure wave equation, the prediction of the far-field sound field of the underwater vehicle is obtained; the calculation formula of the sound pressure wave equation includes:

[0090] In the sound pressure wave equation Indicates pressure. , , Representing coordinate position, in the sound pressure wave equation This indicates the speed at which sound waves propagate in a medium.

[0091] Reference Figure 6 In one embodiment of the present invention, a fluid-structure-acoustic coupling numerical analysis system based on an underwater vehicle is also provided, comprising a parameter acquisition module 1001, a fluid-structure coupling module 1002, and a fluid-structure-acoustic coupling module 1003, wherein: The parameter acquisition module 1001 is used to acquire parameters of the underwater vehicle at multiple time steps.

[0092] The fluid-structure interaction module 1002 is used to perform fluid calculations using the finite volume method and the first parameters of the first time step of the underwater vehicle to obtain the first fluid calculation result of the underwater vehicle; to perform solid calculations using the modal superposition method, the first parameters, and the first flow field force in the first fluid calculation result to obtain the first solid calculation result of the underwater vehicle; to perform fluid calculations using the first control point information of the first solid calculation result, the finite volume method, and the second parameters of the second time step of the underwater vehicle to obtain the second fluid calculation result of the underwater vehicle; to perform solid calculations using the second flow field force of the second fluid calculation result, the modal superposition method, and the second parameters to obtain the second solid calculation result of the underwater vehicle; and to iterate in this manner until the Nth fluid calculation result of the last time step of the underwater vehicle is obtained, where N represents a positive integer.

[0093] The fluid-structure-acoustic coupling module 1003 is used to substitute the Nth fluid calculation result into the sound pressure wave equation to obtain the prediction of the far-field sound field of the underwater vehicle.

[0094] It should be noted that since the fluid-structure-acoustic coupling numerical analysis system based on an underwater vehicle in this embodiment is based on the same inventive concept as the fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle described above, the corresponding content in the method embodiment is also applicable to this device embodiment, and will not be described in detail here.

[0095] refer to Figure 7 In another embodiment of the present invention, an electronic device 6000 is also provided, which can be any type of smart terminal, such as a mobile phone, tablet computer, personal computer, etc.

[0096] Specifically, the electronic device 6000 includes: one or more control processors 6001 and memory 6002. Figure 7 Taking a control processor 6001 and a memory 6002 as an example, the control processor 6001 and the memory 6002 can be connected via a bus or other means. Figure 7 Taking the example of a connection between China and Israel via a bus.

[0097] The memory 6002, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as program instructions / modules corresponding to an electronic device in an embodiment of the present invention. The control processor 6001 executes various functional applications and data processing of a fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle by running non-transient software programs, instructions, and modules stored in the memory 6002, thereby realizing a fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle as described in the above method embodiment.

[0098] The memory 6002 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created using a fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle. Furthermore, the memory 6002 may include high-speed random access memory and non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 6002 may optionally include memory remotely located relative to the control processor 6001, and these remote memories can be connected to the electronic device 6000 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0099] One or more modules are stored in memory 6002. When executed by one or more control processors 6001, a fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle is executed in the above-described method embodiments, for example, the method described above. Figures 1 to 4 The method and steps.

[0100] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0101] It should be noted that since the electronic device in this embodiment is based on the same inventive concept as the above-described fluid-structure-acoustic coupling numerical analysis method based on underwater vehicles, the corresponding content in the method embodiment is also applicable to this device embodiment, and will not be described in detail here.

[0102] One embodiment of the present invention also provides a computer-readable storage medium storing computer-executable instructions for performing: the fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle as described in the above embodiment.

[0103] It should be noted that since the computer-readable storage medium in this embodiment is based on the same inventive concept as the above-described fluid-structure-acoustic coupling numerical analysis method based on underwater vehicles, the corresponding content in the method embodiment is also applicable to this device embodiment, and will not be described in detail here.

[0104] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing data (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired data and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any data delivery medium.

[0105] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0106] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A numerical analysis method for fluid-structure-acoustic coupling based on underwater vehicles, characterized in that, The fluid-structure-acoustic coupling numerical analysis method based on underwater vehicles includes: Obtain parameters for multiple time steps of the underwater vehicle; Fluid calculations are performed using the finite volume method and the first parameters of the first time step of the underwater vehicle to obtain the first fluid calculation result. Solid calculations are then performed using the modal superposition method, the first parameters, and the first flow field force from the first fluid calculation result to obtain the first solid calculation result. Fluid calculations are then performed using the first control point information from the first solid calculation result, the finite volume method, and the second parameters of the second time step of the underwater vehicle to obtain the second fluid calculation result. Solid calculations are then performed using the second flow field force from the second fluid calculation result, the modal superposition method, and the second parameters to obtain the second solid calculation result. This process is iterated until the Nth fluid calculation result of the last time step of the underwater vehicle is obtained, where N represents a positive integer. Substituting the Nth fluid calculation result into the sound pressure wave equation, the prediction of the far-field sound field of the underwater vehicle is obtained; The fluid computation is developed based on the finite volume method. The fluid computation includes: numerically solving the flow field around the underwater vehicle structure using three-dimensional incompressible Navier-Stokes equations based on Eulerian grid discretization; wherein, the inviscid flux in the equations is discretized using the ROE scheme and interpolated using the Van Albada limiter with the 3rd order MUSCL method, the viscous flux in the equations is discretized using the 2nd order central scheme, and the time propagation is performed using the LU-SGS scheme; The fluid calculation also includes turbulence simulation calculation, which uses the LES method to perform turbulence simulation; wherein, the model of the LES method adopts the Vreman eddy viscosity subgrid model; The formula for calculating the first flow field force includes: in, Represents the flow field force. Indicates the time step, therefore the first flow field force up to the second... The formulas for calculating flow field forces are all the same. Indicates the wet noodle element number, and , Indicates the first The coordinates of the center point of each wet surface element Indicates the first The vibration mode at the center point of each wetted surface element Indicates the first The area of ​​each wet noodle unit, To act on the first The surface distribution force vector at the center point of each wetted surface element; the solid calculation includes: The continuous structure of the underwater vehicle is converted into a system with multiple discrete degrees of freedom, and the dynamic equations of the system include: in, , and Let these represent the mass matrix, damping matrix, and stiffness matrix of a dry structure in a vacuum, respectively. , and Let these represent the column vectors of displacement, velocity, and acceleration of discrete nodes in the system, respectively. Indicates a time step. This represents the dynamic force column vectors acting on the wetted surface of the structure by the flow field; The dynamic response characteristics of the system are solved by the modal superposition method, which extracts a finite number of modes; the mode shape displacement matrix corresponding to the finite number of modes includes: in, express The column vector of modal displacements corresponding to the first mode. Represents a positive integer; the method of solving the dynamic response characteristics of the system using modal superposition includes: The discrete nodal displacements of the structure in the system are calculated using the modal superposition method; the formulas for calculating the discrete nodal displacements include: in, and Represent the generalized principal coordinate column vector and the first... Principal coordinate components of the step-by-step mode; The linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape of the floating structure nodes in the system are calculated using the modal superposition method. The calculation formulas for the linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape include: in, Indicates linear displacement. Indicates angular displacement. Indicates the mode shape of linear displacement. Indicates the mode shape of angular displacement; The principal coordinate motion equation of the system is calculated based on the discrete node displacements of the structure; the calculation formula for the principal coordinate motion equation includes: The principal coordinate motion equations , and Let represent the generalized mass matrix, generalized damping matrix, and generalized stiffness matrix of the structural dry modes, respectively. All three matrices are diagonal matrices. This represents the force exerted by the acoustic medium flow field on the wet surface. Represents the force of the acoustic medium flow field on the wet surface The corresponding generalized hydrodynamic column vector, The first derivative of the generalized principal coordinate column vector is given by... The second derivative of the generalized principal coordinate column vector; The vibration velocity response is calculated based on the principal coordinate motion equation, the linear displacement, the linear displacement mode shape, the angular displacement, and the angular displacement mode shape; the calculation formula for the vibration velocity response includes: in, The first derivative of linear displacement. The first derivative represents the mode shape of linear displacement. Indicates the first The first derivative of the principal coordinate component of the step mode.

2. The numerical analysis method for fluid-structure-acoustic coupling based on underwater vehicles according to claim 1, characterized in that, The step of substituting the Nth fluid calculation result into the sound pressure wave equation to obtain the prediction of the far-field sound field of the underwater vehicle includes: The fluid pulsation pressure of the underwater vehicle is obtained from the Nth fluid calculation result; Substituting the fluid pulsating pressure into the sound pressure wave equation, the prediction of the far-field sound field of the underwater vehicle is obtained; the calculation formula of the sound pressure wave equation includes: The sound pressure wave equation Indicates pressure. , , Indicating coordinate position, the sound pressure wave equation in This indicates the speed at which sound waves propagate in a medium.

3. A fluid-structure-acoustic coupling numerical analysis system based on an underwater vehicle, characterized in that, The underwater vehicle-based fluid-structure-acoustic coupling numerical analysis system includes: The parameter acquisition module is used to acquire parameters of the underwater vehicle at multiple time steps. The fluid-structure interaction module is used to perform fluid calculations using the finite volume method and the first parameters of the first time step of the underwater vehicle to obtain the first fluid calculation result of the underwater vehicle; to perform solid calculations using the modal superposition method, the first parameters, and the first flow field force in the first fluid calculation result to obtain the first solid calculation result of the underwater vehicle; to perform fluid calculations using the first control point information of the first solid calculation result, the finite volume method, and the second parameters of the second time step of the underwater vehicle to obtain the second fluid calculation result of the underwater vehicle; to perform solid calculations using the second flow field force of the second fluid calculation result, the modal superposition method, and the second parameters to obtain the second solid calculation result of the underwater vehicle; and to iterate sequentially until the Nth fluid calculation result of the last time step of the underwater vehicle is obtained, where N represents a positive integer; The fluid-structure-acoustic coupling module is used to substitute the Nth fluid calculation result into the sound pressure wave equation to obtain the prediction of the far-field sound field of the underwater vehicle. The fluid computation is developed based on the finite volume method. The fluid computation includes: based on Eulerian grid discretization, numerically solving the flow field around the underwater vehicle structure using the three-dimensional incompressible Navier-Stokes equations; wherein, the inviscid flux in the equations is discretized using the ROE scheme and interpolated using the Van Albada limiter with the 3rd order MUSCL method, the viscous flux in the equations is discretized using the 2nd order central scheme, and the time propagation is performed using the LU-SGS scheme; The fluid calculation also includes turbulence simulation calculation, which uses the LES method to perform turbulence simulation; wherein, the model of the LES method adopts the Vreman eddy viscosity subgrid model; The formula for calculating the first flow field force includes: in, Represents the flow field force. Indicates the time step, therefore the first flow field force up to the second... The formulas for calculating flow field forces are all the same. Indicates the wet noodle element number, and , Indicates the first The coordinates of the center point of each wet surface element Indicates the first The vibration mode at the center point of each wetted surface element Indicates the first The area of ​​each wet noodle unit, To act on the first The surface force vector at the center point of each wetted surface element; the solid calculation includes: The continuous structure of the underwater vehicle is converted into a system with multiple discrete degrees of freedom, and the dynamic equations of the system include: in, , and Let these represent the mass matrix, damping matrix, and stiffness matrix of a dry structure in a vacuum, respectively. , and Let these represent the column vectors of displacement, velocity, and acceleration of discrete nodes in the system, respectively. Indicates a time step. This represents the dynamic force column vectors acting on the wetted surface of the structure by the flow field; The dynamic response characteristics of the system are solved by the modal superposition method, which extracts a finite number of modes; the mode shape displacement matrix corresponding to the finite number of modes includes: in, express The column vector of modal displacements corresponding to the first mode. Represents positive integers; The method of solving the dynamic response characteristics of the system by modal superposition includes: The discrete nodal displacements of the structure in the system are calculated using the modal superposition method; the formulas for calculating the discrete nodal displacements include: in, and Represent the generalized principal coordinate column vector and the first... Principal coordinate components of the step-by-step mode; The linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape of the floating structure nodes in the system are calculated using the modal superposition method. The calculation formulas for the linear displacement, linear displacement mode shape, angular displacement, and angular displacement mode shape include: in, Indicates linear displacement. Indicates angular displacement. Indicates the mode shape of linear displacement. Indicates the mode shape of angular displacement; The principal coordinate motion equation of the system is calculated based on the discrete node displacements of the structure; the calculation formula for the principal coordinate motion equation includes: in, , and Let represent the generalized mass matrix, generalized damping matrix, and generalized stiffness matrix of the structural dry modes, respectively. All three matrices are diagonal matrices. This represents the force exerted by the acoustic medium flow field on the wet surface. Represents the force of the acoustic medium flow field on the wet surface The corresponding generalized hydrodynamic column vector, The first derivative of the generalized principal coordinate column vector is given by... The second derivative of the generalized principal coordinate column vector; The vibration velocity response is calculated based on the principal coordinate motion equation, the linear displacement, the linear displacement mode shape, the angular displacement, and the angular displacement mode shape; the calculation formula for the vibration velocity response includes: in, The first derivative of linear displacement. The first derivative represents the mode shape of linear displacement. Indicates the first The first derivative of the principal coordinate component of the step mode.

4. An electronic device, characterized in that: It includes at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, which, when executed by the at least one control processor, enables the at least one control processor to perform the fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle as described in any one of claims 1 to 2.

5. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the fluid-structure-acoustic coupling numerical analysis method based on an underwater vehicle as described in any one of claims 1 to 2.

Images