Velocity boundary numerical wave generation method based on Abaqus-CEL

Abstract

This paper provides a velocity boundary numerical wave generation method based on Abaqus-CEL. The method creates an Euler domain, divides the Euler domain into an airspace and a material domain, and then divides the material domain into a wave-generating region and a damping wave-absorbing region. The Euler domain is then imported into the Abaqus software as a component. The free surface of the material domain is tracked using the tracer particle method. Velocity boundary functions for regular and irregular waves are set to obtain velocity field data, which are then mapped to the boundary nodes of the Euler domain. Wave generation is then completed by parameter setting and initialization using the Abaqus software. By establishing a parameter mapping relationship between the velocity boundary function and wave theory and reconstructing the theoretical solution of the wave velocity field, a vertical non-uniform velocity distribution consistent with Airy wave theory is directly applied to the computational domain boundary, eliminating the discrepancy between the physical model and the theoretical solution in traditional methods.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical wave generation, and in particular to a velocity boundary numerical wave generation method based on Abaqus-CEL. Background Art

[0002] Numerical wave generation is a key technology in the fields of ocean engineering and computational fluid dynamics. It aims to generate wave fields that conform to theoretical or experimental laws in a virtual water pool through numerical simulation methods, providing a basis for wave load analysis and hydrodynamic performance research of marine structures.

[0003] The traditional wave-making method using a pusher plate requires a long wave-making area to be set up during the numerical simulation process, usually 3-5 times the wavelength. This directly leads to a geometric increase in the number of Euler grids, significantly increasing the consumption of computing resources. Secondly, this method has theoretical defects in setting boundary conditions. The inflow boundary wave velocity it imposes is uniformly distributed along the water depth direction, which is fundamentally inconsistent with the classical Airy theoretical solution in wave theory that the velocity field decays exponentially with water depth. This results in limited simulation accuracy of the near-field wavefront morphology and wave pressure distribution. In addition, the dynamic contact between the pusher plate and the Euler unit will cause complex interface tracking problems, which not only increases the number of iterations of the numerical calculation, but also easily leads to stability problems such as grid distortion, thereby greatly reducing the computational efficiency. Summary of the Invention

[0004] The present invention proposes a velocity boundary numerical wave generation method based on Abaqus-CEL to solve the technical problems of dynamic grid distortion, poor source term stability and insufficient adaptability to complex working conditions in traditional numerical wave generation.

[0005] To solve the above technical problems, the present invention provides a velocity boundary numerical wave generation method based on Abaqus-CEL, comprising the following steps: creating an Euler domain in an Abaqus component, dividing the Euler domain into an air domain and a material domain, dividing the material domain into a wave generation area and a damping wave absorption area, and importing the Euler domain as a component into an assembly; tracking the free liquid surface of the material domain by using a tracer particle method; setting velocity boundary functions for regular waves and irregular waves to obtain velocity field data, and mapping the velocity field data to boundary nodes of the Euler domain; and performing parameter setting and initialization of wave generation preparations by using Abaqus software.

[0006] Preferably, the wave-making zone describes the quasi-incompressibility of water by the us-up state equation, and controls the bulk modulus by the following formula to control the compressibility within a set threshold:

[0007] ;

[0008] Where, For pressure, is the density, is the reference density or initial density, is the reference sound speed or initial sound speed, is the adiabatic index.

[0009] Preferably, meshing is performed for the Euler domain in the mesh interface of the Abaqus software, and the mesh attribute is defined as hexahedron EC3D8R, and the horizontal mesh size satisfies the following expression:

[0010] ;

[0011] Where, represents the horizontal grid length; L represents the characteristic wavelength; T represents the wave period; represents the acceleration due to gravity; d is the water depth.

[0012] The vertical grid is densely packed at the boundary between the airspace and the material domain, i.e., at the free liquid surface, and thinned out away from the free liquid surface. The vertical grid length is Minimum grid length , maximum grid length .

[0013] Preferably, the method for setting the velocity boundary function of the regular wave includes:

[0014] 1) Decompose the velocity amplitude into linear terms and nonlinear correction terms:

[0015] ;

[0016] ;

[0017] Where, is the horizontal spatial analytical field, is the spatial analytical field in the vertical direction; is the wave height; For water depth; is the frequency; is the wave number; is the free liquid level height; the water surface at rest , negative downwards.

[0018] 2) Construct the time phase field and introduce the phase compensation factor By iteratively solving the wavefront equation, the velocity field phase is dynamically adjusted so that the synchronization error between the wavefront motion and the boundary velocity is less than the set threshold:

[0019] ;

[0020] ;

[0021] Where, is the horizontal time phase field; is the time phase field in the vertical direction; Indicates the analysis step time; Indicates the distance in the horizontal direction.

[0022] 3) Set the space-time coupled boundary velocity function at the incident boundary according to the velocity field parameterized model of Airy-Stokes mixed wave theory;

[0023] ;

[0024] ;

[0025] Where, represents the velocity boundary function along the horizontal direction; represents the velocity boundary function along the vertical direction.

[0026] Preferably, the method for setting the velocity boundary function of the irregular wave comprises:

[0027] 1) Discrete the wave energy into frequency components and directional components, the spectral density function is expressed as:

[0028] ;

[0029] Where, is a constant; is the acceleration due to gravity; is the wave angular frequency; is the peak angular frequency; is a constant; is the peak width;

[0030] 2) Direction distribution uses the following function:

[0031] ;

[0032] Where, is the current angle, is the angle of the main propagation direction, is the directional index;

[0033] 3) Synthesize the three-dimensional velocity field by superposition of spectral components:

[0034] ;

[0035] ;

[0036] ;

[0037] Where, represents the velocity boundary function along the horizontal direction; represents the velocity boundary function along the vertical direction; Indicates the number of frequency components; Indicates the number of directional components; represents the wave amplitude of the i-th frequency and j-th direction component; is the wave number of the i-th frequency; is the angular frequency of the i-th frequency; is the propagation direction of the wave in the jth direction; represents the phase of the i-th frequency and j-th direction; represents the phase offset of the i-th frequency and the j-th direction; is the free liquid surface height; For water depth.

[0038] Preferably, the wave number is solved by the following formula:

[0039] .

[0040] Preferably, the length of the wave damping zone is dynamically adjusted according to the real-time wave height using the following formula:

[0041] ;

[0042] Where, Indicates the length of the damping zone; ; L is the characteristic wavelength.

[0043] Preferably, the damping coefficient of the damping wave absorbing zone is set by the following formula:

[0044] ;

[0045] ;

[0046] Where, represents the actual damping coefficient; is the speed of sound; is the horizontal grid size; Indicates density; Indicates the starting coordinates of the damping zone.

[0047] The beneficial effects of the present invention include at least the following: by establishing a parameter mapping relationship between the velocity boundary function and the wave theory and reconstructing the theoretical solution of the wave velocity field, the present invention directly applies a vertical non-uniform velocity distribution that conforms to the Airy wave theory at the boundary of the calculation domain, thereby eliminating the deviation problem between the physical model and the theoretical solution in the traditional method.

[0048] The present invention does not require the installation of a physical pusher plate structure, can shorten the wave-generating area by more than 60%, and effectively reduces the discrete scale of the Euler grid; through theoretical derivation, a mathematical mapping relationship between velocity boundary conditions and wave parameters is established, thereby achieving precise control of parameters such as incident wave height and period; avoiding the contact algorithm between the pusher plate and the fluid domain, reducing the calculation time of a single working condition by about 40%, and significantly improving the computational efficiency of large-scale wave numerical simulation.

[0049] Leveraging the core strengths of the Abaqus-CEL framework, this paper develops a multimodal wave subroutine input system, enabling fully automated parametric generation of regular and irregular waves through a Fortran secondary development interface. This system overcomes the limitations of traditional GUI interface parameter input and deeply couples wave theory solutions with numerical models. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Schematic diagram of a method flow in an embodiment of the present invention;

[0051] Figure 2 Schematic diagram of the Euler domain according to an embodiment of the present invention;

[0052] Figure 3 A schematic diagram of finite element mesh encryption according to an embodiment of the present invention;

[0053] Figure 4 This is a schematic diagram of the result of generating regular waves at stable moments according to an embodiment of the present invention;

[0054] Figure 5 A schematic diagram of the generation result of irregular waves at a stable moment according to an embodiment of the present invention;

[0055] Figure 6 A comparison diagram of the theoretical bounds and experimental values ​​of the regular wave inflow boundary velocity at the stable moment according to an embodiment of the present invention;

[0056] Figure 7 This is a diagram of the irregular wave inflow boundary velocity at the stable moment of an embodiment of the present invention;

[0057] Figure 8 This is a regular wave diagram at a stable moment according to an embodiment of the present invention;

[0058] Figure 9 Schematic diagram of the wave absorbing result of the regular wave damping layer at the stable moment according to an embodiment of the present invention;

[0059] Figure 10 Schematic diagram of irregular waves at a stable moment according to an embodiment of the present invention;

[0060] Figure 11 Schematic diagram of a wave impact breakwater model according to an embodiment of the present invention;

[0061] Figure 12 This is a schematic diagram of a slope impacted by a regular wave at a stable moment according to an embodiment of the present invention;

[0062] Figure 13 Schematic diagram of pressure comparison at breakwater measuring points according to an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0064] Example 1

[0065] like Figure 1 As shown, an embodiment of the present invention provides a velocity boundary numerical wave generation method based on Abaqus-CEL, comprising the following steps: creating an Euler domain, dividing the Euler domain into an air domain and a material domain, dividing the material domain into a wave generation area and a damping wave elimination area, and importing the Euler domain as a component into the Abaqus software; tracking the free liquid surface of the material domain by the tracer particle method; setting velocity boundary functions of regular waves and irregular waves to obtain velocity field data, and mapping the velocity field data to the boundary nodes of the Euler domain; and completing the wave generation by parameter setting and initialization through the Abaqus software.

[0066] Specifically, a 10m×0.25m×3m rectangular Euler domain is created in the component interface of the Abaqus software, and the component name is water. Furthermore, a reference plane is generated by offsetting the base plane, with the bottom surface offset 1.3m upward and the right surface offset 2m to the left. Furthermore, the Euler domain is cut according to the reference plane, and the Euler domain is divided into an air domain and a material domain. The material domain includes a wave-generating zone and a damping zone. The length of the damping zone is determined by formula (8). In this example, the damping zone is set to 2m, as shown in the following example: Figure 2 Indicated;

[0067] Define the cross-sectional properties of the material domain in the Abaqus property interface. First, create the material properties water and zuni. Water is the material property of the water in the wave-making area, and define the density, state equation, and dynamic viscosity. Zuni is the material property of the damping wave-absorbing area, and needs to define the density, state equation, dynamic viscosity, and damping. Secondly, create a cross-sectional property of the material, name it cailiaoyu, and assign both the water and zuni material properties to cailiaoyu. Finally, assign the cross-sectional properties of the cailiaoyu material to the entire water component.

[0068] In this embodiment, the us-up state equation is used to describe the quasi-incompressibility of water, as shown in Equation (1). The bulk modulus is controlled by the pressure-density relationship, and the compressibility is limited to within 0.1%.

[0069] (1)

[0070] Where, For pressure, is the density, is the reference density or initial density, is the reference sound speed or initial sound speed, Is the adiabatic index. , , .

[0071] After that, add an assembly to the Abaqus assembly interface, import the component water, name it water-1, move the position of water-1, and place the incident boundary at the origin of the coordinate axis to facilitate the definition of the subsequent boundary function. , downward is negative;

[0072] In the Abaqus analysis step interface, define a dynamic display analysis, name it step1, and set the analysis step time to 15s. In the field output settings, change the time interval to 100, and select the required output field variables. When setting the analysis step, you can set a restart request in the output dialog box to avoid data loss due to unexpected program interruption.

[0073] Contact is defined on the Abaqus interaction interface. Since this embodiment only includes Euler elements and no Lagrangian elements, contact does not need to be defined. However, numerical simulations involving Euler elements generally define general contact, so only general contact is defined.

[0074] In the Abaqus mesh interface, mesh the Euler domain and define the mesh properties as hexahedron EC3D8R. The horizontal mesh size must meet the wavelength resolution requirements, that is:

[0075] (2)

[0076] Among them, L is the characteristic wavelength, T is the wave period, and d is the water depth. , When the deep water wavelength is 1.56m, the horizontal grid length .

[0077] In the vertical direction, the vertical grid is encrypted near the free liquid surface, and the minimum grid length , the bottom area is sparse to , the model after mesh encryption and sparse processing is as follows Figure 3 shown.

[0078] Define the load, boundary conditions, assign Euler materials and define the initial stress field in the Abaqus load interface. First, apply a force of -9.8N to the entire model in the downward direction along the z-axis; set symmetric velocity boundaries on the lateral and bottom boundaries, set the normal velocity to zero, and the tangential velocity to free, to reduce reflection while preventing the outflow of Euler materials; at the same time, set the left boundary as the Euler incident boundary with free inflow, and the right boundary as the outflow boundary with balanced outflow; assign materials to the Euler component. In the material assignment dialog box, first select the Euler component water, and then specify the wave-making area material instance water1-water1 and the damping area material instance zuni1-water1 respectively.

[0079] Define the initial stress field for the material domain, with the water surface pressure being 0 Pa and the water bottom pressure being 13000 Pa.

[0080] In the Abaqus load interface, define the inflow boundary and set the velocity boundary function. In order to adapt to regular waves and irregular waves, the following velocity boundary function is set in the embodiment of the present invention. It is related to both time and water depth, with the water surface velocity being the fastest and the bottom velocity being the slowest.

[0081] For regular waves, in order to break through the limitation of the traditional separation of linear wave and nonlinear wave models, this embodiment proposes a unified velocity boundary function system: construct a spatial analytical field, and decompose the velocity amplitude into the linear Airy wave and the nonlinear correction term Stokes second-order wave:

[0082] (3)

[0083] (4)

[0084] Formula (3) is the horizontal analytical amplitude field, and formula (4) is the vertical analytical amplitude field, where is the wave height, For water depth, is the frequency, is the wave number, is the free liquid level height, the water surface at rest , negative downwards.

[0085] Afterwards, the time phase field is constructed and the phase compensation factor is introduced , by iteratively solving the wavefront equation and dynamically adjusting the velocity field phase, the synchronization error between the wavefront motion and the boundary velocity is less than 2%;

[0086] (5)

[0087] (6)

[0088] Equation (5) is the horizontal time phase field, and Equation (6) is the vertical time phase field; Indicates the analysis step time; Represents the distance in the horizontal direction, which is 0 at the velocity boundary entrance.

[0089] In this embodiment, a multi-level boundary control technology system is proposed to address the common problems of reflected wave interference, three-dimensional expansion distortion, and computational efficiency bottlenecks in numerical wave tanks. Through theoretical innovation and algorithm optimization, high-fidelity simulation of wave fields is achieved. At the incident boundary, a spatiotemporal coupled boundary velocity function is set according to the velocity field parameterized model of the Airy-Stokes hybrid wave theory.

[0090] (7)

[0091] (8)

[0092] As shown in Equation (7), the analytical field function related to spatial variation is set in the main X direction and the time-dependent phase field function Similarly, as shown in formula (8), the analytical field function related to spatial variation is also set in the secondary Z direction and the time-dependent phase field function .

[0093] Set the horizontal velocity boundary condition at the inflow boundary, named BC-x, with the direction outward along the x-axis, and select the distribution analytical field function as , the time phase field is ; Set the vertical velocity boundary condition, named BC-z, with the direction downward along the z axis, and select the distribution analytical field function as , the time phase field is ;

[0094] For irregular wave simulation, the wave energy is discretized into frequency components and directional components, and its spectral density function is expressed as:

[0095] (9)

[0096] In the formula is a constant, usually 0.0081. is the acceleration due to gravity, usually taken as 9.81 , is the wave angular frequency, is the peak angular frequency, corresponding to the maximum energy in the spectrum, The constant represents the peak factor, which determines the sharpness of the spectrum peak and is usually set to 3.3. is the peak width parameter, usually taken as 0.07.

[0097] The direction distribution is then applied using the following function:

[0098] (10)

[0099] Where, is the current angle, is the angle of the main propagation direction, is the directional index, which determines the width of the directional function, The larger the value of , the narrower the directivity function, indicating that the propagation direction of the wave is more concentrated.

[0100] The three-dimensional velocity field is synthesized by superposition of spectral components:

[0101] (11)

[0102] (12)

[0103] (13)

[0104] Where, represents the velocity boundary function along the horizontal direction; represents the velocity boundary function along the vertical direction; is the number of frequency components, which indicates the number of different frequencies considered in the wave spectrum; is the number of directional components, indicating the number of decompositions of each frequency component in different directions; represents the wave amplitude of the i-th frequency and j-th direction component; is the wave number of the i-th frequency; is the angular frequency of the i-th frequency; is the propagation direction of the wave in the jth direction; represents the phase of the i-th frequency and j-th direction; represents the phase offset of the i-th frequency and the j-th direction; is the free liquid surface height; For water depth.

[0105] Finally, set the initial parameters of the irregular waves, such as gravitational acceleration, effective wave height, spectral peak period, spectral peak factor and initial water depth; set the horizontal velocity boundary condition at the inflow boundary, named BC-x, with the direction outward along the x-axis, and select user-defined as the amplitude function.

[0106] For example, in this embodiment, the dispersion equation is solved by iteratively using the Brent algorithm to perform reverse deduction to determine the wave number data in the above formula:

[0107] (14)

[0108] Among them, is the wave angular frequency, in rad / s; is the wave number, in rad / m; g is the acceleration due to gravity, which is 9.81 m / s².

[0109] In this embodiment, leveraging the core strengths of the Abaqus-CEL framework, a multimodal wave subroutine input system was developed. This system, via a Fortran secondary development interface, enables fully automated parametric generation of regular and irregular waves. This system overcomes the limitations of traditional GUI interface parameter input and deeply couples wave theory solutions with numerical models.

[0110] Specifically, the Abaqus user subroutine VUAMP-WaveGenerator is developed to build a bidirectional data channel between the wave parameter analysis engine and the numerical model; at the input layer, a JSON configuration file is used to dynamically read the key parameters of the wave spectrum, including the peak shape factor of the JONSWAP spectrum. To characterize the sharpness of the spectrum peak; the spectrum peak frequency The frequency corresponding to the maximum distribution of wave energy; directional distribution function To describe the distribution characteristics of wave energy along the propagation direction; the kernel layer is based on the Fortran-Python hybrid programming architecture, and uses the FFTW3 fast Fourier transform library to efficiently discretize the wave spectrum and synthesize multi-directional irregular wave velocity fields in real time; the output layer uses shared memory technology to directly map the generated velocity field data to the Abaqus Euler domain boundary nodes, and the data delay is strictly controlled within 1 millisecond to ensure the spatiotemporal synchronization of wave propagation.

[0111] Then create a job, name it job-1, edit the job, select the fortran subroutine in the general interface, and make sure to put the subroutine file and the abaqus file in the same folder.

[0112] Create tracer particles. Since the Euler unit cannot directly output the displacement of the wave surface, it is necessary to use the tracer particle method to assist in outputting the wave surface displacement and use the VOF function Accurately capture the dynamic deformation of the free liquid surface; further, select the static water surface grid nodes to establish a tracer particle set, name the node set shizong, and use the keyword tracerparticle in the inp document to add the input position and output requirements of the tracer particles.

[0113] Finally, create a new job-1 of type recovery in the Abaqus work interface, set it to multi-core calculation, submit the calculation, complete the wave generation, and the results of the regular wave generation at the stable moment are as follows: Figure 4 As shown, the irregular wave generation results at the stable moment are as follows Figure 5 As shown in the figure, the comparison between the theoretical boundary and the experimental value of the regular wave inflow boundary velocity at the stable moment is shown in Figure 6 As shown in the figure, the comparison between the theoretical boundary and the experimental value of the irregular wave inflow boundary velocity at the stable moment is shown in Figure 7 As shown, the regular wave diagram at the stable moment is as follows Figure 8 As shown, the wave elimination results of the regular wave damping layer at the stable moment are as follows Figure 9 As shown, the irregular wave diagram at the stable moment is as follows Figure 10 shown.

[0114] Example 2

[0115] This embodiment provides a method for initializing a damping and wave-breaking layer based on the first embodiment.

[0116] An exponential damping layer is set at the outflow boundary. A damping layer is set up in the area, using a hyperbolic tangent function for gradual transition. The subsequent correction of the momentum equation involves adding an artificial dissipation term to the Navier-Stokes (NS) equation. The optimal damping coefficient is determined through the dispersion relationship, so that the reflected wave energy attenuation rate is greater than 98%. The damping layer length is dynamically adjusted based on real-time wave height monitoring data. ,in Automatic optimization based on wave nonlinearity.

[0117] Specifically, in this embodiment, the expression of the damping coefficient is:

[0118] (15)

[0119] (16)

[0120] Where, represents the actual damping coefficient; is the speed of sound; is the horizontal grid size; Indicates density; Indicates the starting coordinates of the damping zone.

[0121] Example 3

[0122] This embodiment is a numerical simulation experiment of waves impacting breakwaters using the wave-making method of Example 1. This experiment is a calibration of an indoor experiment. The wave-making method of Example 1 is used to achieve the effect of regular waves impacting breakwaters. This model includes Euler units representing waves and Lagrangian units representing structures. By comparing the results of the simulation experiment with the results of the indoor experiment, the feasibility and reliability of the wave-making method of the present invention in fluid-solid coupling numerical simulation are verified, thereby broadening the application of the CEL method.

[0123] See Figure 11 、 Figure 12 and Figure 13 As shown in the figure, they are respectively a model diagram of wave impacting the breakwater, a schematic diagram of the slope impacted by regular waves at the stable moment, and a pressure comparison diagram of the breakwater measuring points. When implemented, the following steps are included:

[0124] The first step is to create an Euler component in the Abaqus component interface to represent the water body, named water, a deformed body representing the soil body, named soil, and a deformed body representing the breakwater, named fangbodi. The Euler component is divided into a material domain and an air domain, with specific dimensions as follows: Figure 11 shown.

[0125] The second step is to define the cross-sectional properties of the material domain in the Abaqus property interface. First, create the material properties water, soil, and fangbodi. Water is the material property of the water in the wave-making area. It is necessary to define the density, state equation, and dynamic viscosity. The state equation of water is us-up. Soil is the material property of the soil. It is necessary to define the density, elastic modulus, Poisson's ratio, and Mohr-Coulomb plasticity. Fangbodi is the material property of the concrete breakwater. It is necessary to define the density, elastic modulus, Poisson's ratio, and concrete damage plasticity. Further create cross-sectional properties and assign the cross-sectional properties to the corresponding components.

[0126] The third step is to add an assembly to the Abaqus assembly interface, import the components water, soil, and fangbodi, and name them as assemblies water-1, soil-1, and fangbodi-1 respectively. Move the assembly position and place the incident boundary of water-1 at the origin of the coordinate axis to facilitate the definition of the subsequent boundary function. , downward is negative;

[0127] In the fourth step, define a dynamic display analysis in the Abaqus analysis step interface, name it step 1, set the analysis step time to 30 seconds, change the time interval to 100 in the field output settings, and select the required output field variables. Furthermore, when setting the analysis step, you can set a restart request in the output dialog box to avoid data loss due to unexpected program interruptions.

[0128] Step 5: Define the contact in the Abaqus interaction interface. Use face-to-face contact between the breakwater and the soil, and use general contact between the water, the breakwater, and the soil. Set the contact properties water-fangbodi and fangbodi-soil to define the normal and tangential behaviors, respectively.

[0129] Step 6. Divide the mesh for the components in the Abaqus mesh interface. The water mesh attribute is hexahedron EC3D8R, and the breakwater and soil mesh attribute is hexahedron C3D8R.

[0130] Step 7: Define loads, boundary conditions, assign Euler materials, and define initial stress fields in the Abaqus load interface, such as Figure 11 As shown, first, a force of -9.8N is applied to the entire model in the downward direction along the z-axis;

[0131] Symmetrical velocity boundaries are set on the lateral and bottom boundaries of the water body, the normal velocity is set to zero, the left boundary is set to the Euler incidence boundary, and the inflow mode is free inflow; the bottom surface of the soil is set as a fixed boundary to limit the displacement and rotation in all directions, and the side is set as a symmetric displacement boundary to limit the displacement in the corresponding direction; symmetric displacement boundaries are set on the side of the breakwater to limit the lateral displacement.

[0132] Assign materials to the Euler component. In the Material Assignment dialog box, first select the Euler component water, and then specify the material domain.

[0133] Define the initial stress field for the material domain, with the water surface pressure being 0 Pa and the water bottom pressure being 13000 Pa.

[0134] In the eighth step, the velocity boundary function is defined at the inflow boundary in the Abaqus load interface. The specific steps are the same as the method for setting the regular wave velocity boundary function in Example 1.

[0135] The ninth step is to create tracer particles. Since the Euler unit cannot directly output the displacement of the wave surface, the tracer particle method is needed to assist in outputting the wave surface displacement. Furthermore, the still water surface mesh nodes are selected to establish a tracer particle set. The node set is named shizong. The keyword tracer particle is used in the inp document to add the input position and output requirements of the tracer particles.

[0136] Step 10. Create a new job-1 of type recovery in the Abaqus work interface, set it to multi-core calculation, submit the calculation, and the schematic diagram of the regular wave impacting the slope at the stable moment is as follows: Figure 12 As shown in the figure, the pressure comparison of the breakwater measuring point is Figure 13 shown.

[0137] The technical features of the above embodiments may be combined in any manner. To simplify the description, not all possible combinations of the technical features in the above embodiments are described. Only preferred embodiments of the present invention are presented. While the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. As long as there are no conflicts in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] It should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A velocity boundary numerical wave generation method based on Abaqus-CEL, characterized by: The following steps are involved: An Euler domain is created in an Abaqus component, the Euler domain is divided into an airspace and a material domain, the material domain is divided into a wave-generating region and a damping wave-absorbing region, and the Euler domain is imported into an assembly as a component; the free surface of the material domain is tracked using a tracer particle method; velocity boundary functions for regular and irregular waves are set to obtain velocity field data, and the velocity field data is mapped to boundary nodes of the Euler domain; and parameter settings and initialization of wave generation preparations are performed using Abaqus software. Methods for setting the velocity boundary function of regular waves include: 1) Decompose the velocity amplitude into linear terms and nonlinear correction terms: ； ； Where, is the horizontal spatial analytical field, is the spatial analytical field in the vertical direction; is the wave height; For water depth; is the frequency; is the wave number; is the free liquid level height; the water surface at rest , downward is negative; 2) Construct the time phase field and introduce the phase compensation factor By iteratively solving the wavefront equation, the velocity field phase is dynamically adjusted so that the synchronization error between the wavefront motion and the boundary velocity is less than the set threshold: ； ； Where, is the horizontal time phase field; is the time phase field in the vertical direction; Indicates the analysis step time; Indicates the distance along the horizontal direction; 3) Set the space-time coupled boundary velocity function at the incident boundary according to the velocity field parameterized model of Airy-Stokes mixed wave theory; ； ； Where, represents the velocity boundary function along the horizontal direction; represents the velocity boundary function along the vertical direction.

2. The velocity boundary numerical wave generation method based on Abaqus-CEL according to claim 1 is characterized in that: The wave-making zone describes the quasi-incompressibility of water by the us-up state equation, and controls the bulk modulus by the following formula to control the compressibility within a set threshold: ； Where, For pressure, is the density, is the reference density or initial density, is the reference sound speed or initial sound speed, is the adiabatic index.

3. The velocity boundary numerical wave generation method based on Abaqus-CEL according to claim 1 is characterized in that: In the mesh interface of the Abaqus software, mesh the Euler domain, define the mesh attribute as hexahedron EC3D8R, and the horizontal mesh size satisfies the following expression: ； Where, Indicates the horizontal grid length; L indicates the characteristic wavelength; T is the wave period; represents the acceleration due to gravity; d is the water depth; The vertical grid is densely packed at the boundary between the airspace and the material domain, i.e., at the free liquid surface, and thinned out away from the free liquid surface. The vertical grid length is Minimum grid length , maximum grid length .

4. The velocity boundary numerical wave generation method based on Abaqus-CEL according to claim 1 is characterized in that: Methods for setting the velocity boundary function of irregular waves include: 1) Discrete the wave energy into frequency components and directional components, the spectral density function is expressed as: ； Where, is a constant; is the acceleration due to gravity; is the wave angular frequency; is the peak angular frequency; is a constant; is the peak width; 2) Direction distribution uses the following function: ； Where, is the current angle, is the angle of the main propagation direction, is the directional index; 3) Synthesize the three-dimensional velocity field by superposition of spectral components: ； ； ； Where, represents the velocity boundary function along the horizontal direction; represents the velocity boundary function along the vertical direction; Indicates the number of frequency components; Indicates the number of directional components; represents the wave amplitude of the i-th frequency and j-th direction component; is the wave number of the i-th frequency; is the angular frequency of the i-th frequency; is the propagation direction of the wave in the jth direction; represents the phase of the i-th frequency and j-th direction; represents the phase offset of the i-th frequency and the j-th direction; is the free liquid surface height; For water depth; Indicates the analysis step time; Indicates the distance in the horizontal direction.

5. The velocity boundary numerical wave generation method based on Abaqus-CEL according to claim 1 or 4, characterized in that: The wave number is solved by the following formula: ； Where, is the wave number.

6. The velocity boundary numerical wave generation method based on Abaqus-CEL according to claim 1 is characterized by: The length of the damping zone is dynamically adjusted according to the real-time wave height using the following formula: ； Where, Indicates the length of the damping zone; ; L is the characteristic wavelength.

7. The velocity boundary numerical wave generation method based on Abaqus-CEL according to claim 6, characterized in that: The damping coefficient of the damping wave-absorbing zone is set by the following formula: ； ； In the formula represents the actual damping coefficient; is the speed of sound; is the horizontal grid size; Indicates density; Indicates the distance along the horizontal direction; Indicates the starting coordinates of the damping zone.

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