Wind wave-seabed-pile foundation-photovoltaic array multi-physics field coupling calculation system for ocean photovoltaic power station

Abstract

The invention discloses a wind wave-seabed-pile foundation-photovoltaic array multi-physics field coupling calculation system for an ocean photovoltaic power station. The system comprises a wave model construction module, a photovoltaic array wind load numerical simulation module and a multi-physics field coupling numerical model integration module. The wave model construction module is used for extracting wave elements and constructing a wave model; the photovoltaic array wind load numerical simulation module is used for performing photovoltaic array wind load numerical simulation based on the extracted wave elements and the constructed wave model; and the multi-physics field coupling numerical model integration module is used for carrying out multi-physics field coupling numerical model integration, solving and verification based on a numerical simulation structure. According to the method, the wind wave load, the seabed seepage field, the pile foundation stress field and the photovoltaic array wind field are cooperatively calculated by building the multi-field dynamic coupling model, and therefore the accuracy and reliability of offshore photovoltaic power station pile foundation bearing performance evaluation are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of marine photovoltaic engineering multi-physical field coupling calculation, and particularly relates to a wind wave-seabed-pile foundation-photovoltaic array multi-physical field coupling calculation system for a marine photovoltaic power station. BACKGROUND

[0002] During the service period of the offshore photovoltaic power station, the bearing performance of the pile foundation is significantly affected by the multi-physical field coupling effect formed by the interaction of the wind wave load, the seabed soil body characteristics and the photovoltaic array structure. The existing technology mainly adopts a single physical field independent modeling method to analyze the wind wave load, the soil body response and the structural dynamic characteristics, and lacks systematic research on the dynamic coupling effect of the "wind wave-seabed-pile foundation-photovoltaic array" system. For example, the traditional method often ignores the disturbance effect of wave impact on the pile-soil interface, the influence of the wind load on the wake effect of the photovoltaic array and the cumulative effect of the soil pore water pressure diffusion on the long-term stability of the pile foundation, resulting in that the calculation results deviate from the actual working conditions. In the actual operation of the photovoltaic power station project, some pile foundations have appeared to sink, which highlights the deficiency of the existing method in accurately evaluating the long-term bearing performance of the pile foundation and the overall safety of the system. Therefore, it is urgent to develop an integrated multi-physical field coupling calculation system to solve the key technical problems of the isolation of multi-field analysis, the lack of coupling mechanism and the inaccurate evaluation of the long-term bearing performance of the photovoltaic pile foundation in the existing technology. SUMMARY

[0003] To solve the problems in the prior art, the application provides a wind wave-seabed-pile foundation-photovoltaic array multi-physical field coupling calculation system for a marine photovoltaic power station, which aims to establish a multi-field dynamic coupling model, cooperatively calculate the wind wave load, the seabed seepage field, the pile foundation stress field and the photovoltaic array wind field, solve the problem of the lack of coupling effect caused by the independent analysis of the multi-physical field in the prior art, and thus improve the accuracy and reliability of the bearing performance evaluation of the offshore photovoltaic power station pile foundation.

[0004] To achieve the above-mentioned purpose, the application provides the following scheme:

[0005] A wind wave-seabed-pile foundation-photovoltaic array multi-physical field coupling calculation system for a marine photovoltaic power station, the system comprising: a wave model construction module, a photovoltaic array wind load numerical simulation module and a multi-physical field coupling numerical model integration module.

[0006] The wave model construction module is used for wave element extraction and wave model construction.

[0007] The photovoltaic array wind load numerical simulation module is used for photovoltaic array wind load numerical simulation based on the extracted wave elements and the constructed wave model.

[0008] The multi-physical field coupling numerical model integration module is configured to perform multi-physical field coupling numerical model integration, solving and verification based on a structure of numerical simulation.

[0009] Preferably, the wave model construction module comprises a data base unit, a model establishment unit and an output parameter unit.

[0010] The data base unit is configured to collect measured wave spectrum data and tide data of an engineering sea area for no less than 10 years.

[0011] The model establishment unit is configured to establish a non-steady water pressure wave flume numerical model based on OlaFlow.

[0012] The output parameter unit is configured to calculate time history curves of water pressure around a pile in a wave period, water pressure on a seabed surface in the wave period, and dynamic pressure distribution on a variable-diameter pile impact contact surface, and to establish a wave force correction method considering the pile diameter mutation effect.

[0013] Preferably, in the non-steady water pressure wave flume numerical model, the calculation domain size is set as: length direction ≥ 5 times the design wave length, width direction ≥ 5 times the pile diameter, and height direction ≥ 2 times the water depth; the relaxation zone wave making and wave absorbing technology and the VOF method are used to track the free liquid surface; the k-ε turbulence model is used to simulate the wave breaking process; and the grid resolution in the near-pile area is controlled to be ≤ 0.1 m.

[0014] Preferably, the process of calculating the time history curves of water pressure around the pile in the wave period comprises:

[0015] A series of pressure monitoring points are arranged on the pile foundation surface along the water depth direction;

[0016] In the simulation process, the functionObject of OpenFOAM is used to record the change of pressure on each monitoring point over time;

[0017] The simulation is run so that the simulation duration covers multiple wave periods;

[0018] The pressure data of each monitoring point are extracted from the simulation results, the static water pressure is deducted, and the time history curve of water pressure around the pile, i.e. the data of the change of pressure over time, is obtained;

[0019] The process of calculating the water pressure on the seabed surface in the wave period comprises:

[0020] A series of pressure monitoring points are arranged on the seabed surface, covering the area around the pile foundation and the free seabed within a set range;

[0021] The probes are used to record the change of pressure of the pressure monitoring points over time;

[0022] Extract the time history data of pressure on the seabed surface, and similarly subtract the hydrostatic pressure to obtain the data on the change of dynamic water pressure on the seabed surface over time;

[0023] The process of calculating the dynamic pressure distribution at the impact contact surface of a variable-diameter pile includes:

[0024] Define one or more monitoring surfaces in the diameter abrupt change region, and arrange pressure monitoring points inside the diameter abrupt change region and in the preset surrounding area;

[0025] Record the pressure data at the monitoring points throughout the entire wave cycle;

[0026] Extract the pressure distribution of the monitored surface at each time step, and analyze the spatial distribution and temporal variation of dynamic pressure, i.e., hydrodynamic pressure, in the abrupt change region.

[0027] The process of establishing a wave force correction method that considers the effect of sudden changes in pile diameter includes:

[0028] A correction factor is introduced based on the Morison equation to correct the drag force and inertial force terms.

[0029] Preferably, the photovoltaic array wind load numerical simulation module includes: a data collection unit, a wind field modeling unit, a working condition design unit, and a data output unit;

[0030] The data collection unit is used to collect measured wind element data of the engineering sea area for no less than 10 years;

[0031] The wind field modeling unit is used to construct a numerical model of the atmospheric boundary layer wind field for photovoltaic arrays based on OpenFOAM. The inlet length of the computational domain is set to be no less than 8 times the height of the photovoltaic panel. The boundary conditions are velocity inlet and pressure outlet.

[0032] The operating condition design unit is used to set multi-parameter operating condition combinations, including photovoltaic panel tilt angle, design wind speed, array spacing and array arrangement.

[0033] The data output unit is used to extract and generate a cloud map of the wind pressure coefficient distribution on the photovoltaic panel surface; establish a correction coefficient for the interference effect between multiple panels; convert the wind pressure coefficient into an equivalent wind load acting on the structural nodes based on the quasi-static load conversion assumption; and finally construct a standardized wind load database.

[0034] Preferably, in the numerical model of the atmospheric boundary layer wind field for the photovoltaic array, the governing equations for wind field simulation include:

[0035] Continuity equation: In the formula, U is the wind speed vector;

[0036] The momentum equation is: In the formula, t is time, and ρ aFor air density, ν eff S is the effective dynamic viscosity coefficient, S is the source term, ▽ is the Nabla operator, and p is the pressure.

[0037] The turbulent kinetic energy k equation is: In the formula, k is the turbulent kinetic energy, ω is the specific dissipation rate, and σ is the kinetic energy. k For the turbulent Prandtl number k, P k For the turbulence generation term, β * Model constants, where ν is the molecular kinematic viscosity coefficient. t The turbulent eddy viscosity coefficient;

[0038] The equation for the specific dissipation rate ω is: In the formula, γ is the model constant, β is the model constant, and σ is the model constant. ω For the ratio of dissipation rate to Prandtl number, CD kω This is a cross-diffusion term.

[0039] Preferably, the wind pressure coefficient C on the photovoltaic panel surface is extracted and generated. p The process of creating a distribution cloud map includes:

[0040] Extracting C from the surface of photovoltaic panels p value;

[0041] Calculate C p Statistics include minimum, maximum, mean, and standard deviation;

[0042] Based on C p Statistics, generating C p Distribution cloud map;

[0043] The process of establishing the correction coefficient for inter-board interference effects includes:

[0044] Two simulations were conducted, one of which involved an isolated photovoltaic panel, where a single photovoltaic panel was placed and its C value was obtained. p The first value is the photovoltaic array, which simulates the entire array and records the position and average C of each panel. p value;

[0045] Based on the simulation results, the interference correction coefficient η is calculated according to the position coordinates (i,j) of different points on the photovoltaic panel. ij ;

[0046] The process of converting wind pressure coefficients into equivalent wind loads acting on structural nodes and constructing a standardized wind load database includes:

[0047] The wind pressure on the surface of the photovoltaic panel is converted into nodal forces in the finite element model, using the following formula:

[0048]

[0049] In the formula, Fnode Let N be the equivalent wind load vector at each node. e For the number of units, C p,k Let q be the wind pressure coefficient of unit k. ref For the reference point, A k Surface area of ​​unit k, n k N is the element normal vector. k (x node Unit shape function;

[0050] Three tables are designed to form a standardized wind load database. Table 1 stores the operating condition information, Table 2 stores the load components of each node, and Table 3 stores the total force, torque, and C of each photovoltaic panel. p Statistics.

[0051] Preferably, the multiphysics coupled numerical model integration module includes: an interface development unit, a solver design unit, and a model verification and correction unit;

[0052] The interface development unit is used to develop finite element-specific interface subroutines to realize the real-time and dynamic loading of wave pressure field data calculated by OlaFlow and wind load field data calculated by OpenFOAM onto the nodes of the finite element structural model; a bilinear interpolation algorithm is used to make the load data continuous in both spatial and temporal dimensions.

[0053] The solver design unit is used to employ an explicit-implicit hybrid solution strategy; and to achieve bidirectional data interaction and synchronous solution between wave field, wind field and structure field through parallel computing technology;

[0054] The model verification and correction unit is used to compare and analyze the differences in pile top displacement response under independent calculation and coupled calculation, taking the typical photovoltaic subsystem of "four piles-single support" as the verification object, and optimize and adjust the interface transfer function parameters.

[0055] Compared with existing technologies, the multiphysics coupling calculation system for wind and waves, seabed, pile foundation, and photovoltaic array provided by this invention has the following main technical advantages:

[0056] 1. Breaking through the limitations of single-field analysis, achieving dynamic collaborative calculation of multiple fields: It innovatively realizes the dynamic coupling calculation of wind and wave loads, seabed seepage field, pile foundation stress field and photovoltaic array wind field, effectively solving the problem of missing coupling effect caused by traditional independent modeling of single physical fields.

[0057] 2. Significantly improve the accuracy of pile foundation bearing capacity assessment: By introducing the wave force correction method (considering sudden changes in pile diameter), establishing a standardized wind load database, and optimizing the multi-field coupling interface, the deviation between the calculation results and the actual working conditions is greatly reduced, providing a high-precision basis for assessing the long-term bearing capacity and system safety of pile foundations.

[0058] 3. Enhance the engineering applicability and guidance in complex marine environments: Support the simulation of extreme and long-term marine environmental loads such as typhoons and tides, providing key and quantitative technical support for the structural design optimization of offshore photovoltaic power station pile foundations and the formulation of full life cycle operation and maintenance strategies. Attached Figure Description

[0059] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a schematic diagram of a multiphysics field coupling calculation system for wind, waves, seabed, pile foundation, and photovoltaic array used in an embodiment of the present invention.

[0061] Figure 2 This is a technical roadmap for a multiphysics field coupling calculation system for wind, waves, seabed, pile foundation, and photovoltaic array used in an embodiment of the present invention. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] Example 1

[0065] This invention provides a multiphysics coupling calculation system for wind, waves, seabed, pile foundation, and photovoltaic array for marine photovoltaic power plants. The system includes: a wave model construction module, a photovoltaic array wind load numerical simulation module, and a multiphysics coupling numerical model integration module.

[0066] The wave model building module is used for wave element extraction and wave model building.

[0067] The photovoltaic array wind load numerical simulation module is used to perform numerical simulation of photovoltaic array wind load based on extracted wave elements and constructed wave models.

[0068] The multiphysics coupled numerical model integration module is used for the integration, solution and verification of multiphysics coupled numerical models based on numerical simulation structures.

[0069] In this embodiment, the wave model construction module includes: a data foundation unit, a model building unit, and an output parameter unit;

[0070] Data collection: Collect at least 10 years of measured wave spectrum data (including wave height, period, and direction) and tidal data for the engineering sea area.

[0071] A numerical model of a non-hydrostatic pressure wave tank was established based on OlaFlow:

[0072] Model dimensions: set to ≥5 times the design wavelength in the length direction, ≥5 times the pile diameter in the width direction, and ≥2 times the water depth in the height direction. The mesh resolution of the near-pile area of ​​the water tank model is controlled to ≤0.1m.

[0073] Wave generation technique: Stokes I is used (wave generation methods mainly include Stokes I, II, and solitary waves, etc., Stokes I is used as an example here), and the implicit equation for wavelength L is:

[0074]

[0075] In the formula, L is the wavelength, T is the period, g is the gravitational acceleration, h is the water depth, tanh is the hyperbolic tangent function, k is the wave number, ω is the wave frequency, and c is the wave speed.

[0076] Wave cancellation technology: This involves applying precisely controlled velocity boundary conditions at the exit boundary (the core of which is real-time calculation and application of wave motion with the opposite phase and equal amplitude to the reflected wave), causing the incident wave to cancel out the artificially generated "anti-phase wave." The total wavefront rise at the boundary is η. total It can be decomposed into:

[0077] η total =η i +η r (5)

[0078] In the formula, η i For the wavefront elevation of the incident wave at the boundary (which needs to be eliminated), η r To raise the wavefront of the reflected wave at the boundary (to avoid generating).

[0079] An absorption velocity field u is applied at the boundary. absorb This causes the wavefront height to rise by η due to the active wave-damping boundary. a =-η i Thus achieving η total =0.

[0080] A monitoring point is set at Δx = 0.2L in front of the boundary. The wavefront rise η at time t at the monitoring point is recorded. monitor (t) is:

[0081]

[0082] In the formula, H is the wave height of the incident wave, ω is the circular frequency of the wave, t is time, k is the wave number, Δx is the horizontal distance from the monitoring point to the boundary, and L is the wavelength.

[0083] The incident wave at the boundary at time t is:

[0084]

[0085] Absorption velocity field u absorb for:

[0086]

[0087] VOF method for tracking free surface:

[0088] Define the phase distribution by a volume fraction function α, and determine the free surface by solving the volume fraction transport equation to track the interface motion.

[0089] The volume fraction function α is:

[0090]

[0091] The volume fraction transport equation is:

[0092]

[0093] In the formula, α is the liquid volume fraction, t is time, and u is the fluid velocity vector.

[0094] k-ε turbulence model for simulating wave breaking process:

[0095] During wave breaking, the water flow transitions from laminar to turbulent, and energy is transferred from mean flow to turbulent fluctuations, ultimately dissipating as heat. The k-ε model is achieved by solving the following equations:

[0096] The continuity equation is:

[0097] ▽·u=0(11)

[0098] In the formula, ▽ is the nabla operator, and u is the fluid velocity vector.

[0099] The momentum equation is:

[0100]

[0101] In the formula, ν is the molecular kinetic viscosity coefficient, ν tρ is the turbulent eddy viscosity coefficient, p is the density, and g is the pressure.

[0102] The turbulent kinetic energy k equation is:

[0103]

[0104] In the formula, k is the turbulent kinetic energy, ε is the turbulent dissipation rate, and σ is the turbulent energy. k For the turbulent Prandtl number k, P k This is a turbulence generation term.

[0105] The equation for the turbulent dissipation rate ε is:

[0106]

[0107] In the formula, C ε1 C is the coefficient for the turbulence generation term. ε2 Turbulent dissipation coefficient.

[0108] Data output:

[0109] Output the time history curve of the water pressure around the pile during the wave cycle:

[0110] a. Arrange a series of pressure monitoring points on the surface of the pile foundation along the water depth direction (e.g., from the seabed to above the still water surface, spaced 0.5m apart).

[0111] b. During the simulation, OpenFOAM's functionObject is used to record the pressure changes at each monitoring point over time.

[0112] c. Run the simulation to ensure that the simulation duration covers multiple wave cycles.

[0113] d. Post-processing: Extract the pressure data of each monitoring point from the simulation results, subtract the hydrostatic pressure (i.e., dynamic water pressure), and obtain the data on the change of water pressure around the pile over time.

[0114] • Output the water pressure on the seabed surface during the wave cycle:

[0115] a. Arrange a series of pressure monitoring points on the seabed surface (i.e., the bottom of the tank), covering the area around the pile foundation and a certain range of the free seabed.

[0116] b. Similarly, use probes to record how the pressure at these points changes over time.

[0117] c. Extract the time history data of the seabed surface pressure during post-processing. Similarly, subtract the hydrostatic pressure (if the hydrostatic pressure is already included in the total pressure) to obtain the data on the change of the hydrodynamic pressure on the seabed surface over time.

[0118] • Dynamic pressure distribution at the impact contact surface of variable diameter piles:

[0119] a. Define one or more monitoring surfaces (i.e., a portion of the pile surface) in the area of ​​abrupt diameter change, and arrange dense pressure monitoring points in and around this area.

[0120] b. Record the pressure data of these monitoring points throughout the entire wave cycle.

[0121] c. Extract the pressure distribution data of the monitored surface at each time step.

[0122] • Establish a wave force correction method that takes into account the effect of sudden changes in pile diameter.

[0123] A correction factor is introduced into the traditional Morison equations to correct for the drag force and inertial force terms. The correction factor is determined by k. d Horizontal drag force correction factor and k i The horizontal inertial force correction factor consists of two parts. Taking this as an example, the corrected Morison equation is:

[0124] F = k d F d +k i F i (15)

[0125] In the formula, F is the horizontal wave force acting at any height of the pile. d For horizontal drag force, F i For horizontal inertial force; k d k is the horizontal drag force correction factor. i This is the correction factor for horizontal inertial force.

[0126]

[0127] In the formula, D1 is the upper diameter of the variable diameter pile, and D2 is the lower diameter; a, b, c, and d are undetermined coefficients for correction, obtained through fitting; K c For Keulegan-Carpenter numbers.

[0128] In this embodiment, the photovoltaic array wind load numerical simulation module includes: a data collection unit, a wind field modeling unit, a working condition design unit, and a data output unit;

[0129] Data collection: Collect at least 10 years of measured wind element data (including wind speed and wind direction) for the engineering sea area.

[0130] A numerical model of the wind field of a photovoltaic array was constructed based on OpenFOAM:

[0131] Geometric Model: The photovoltaic module is defined using a tilted flat plate, and the supporting structure is defined using thin cylinders. The inlet length is ≥8 times the photovoltaic panel height (8H), the outlet length is ≥15H, the width is ≥10 times the array width, and the height is ≥5H (H is the photovoltaic panel height). The area around the photovoltaic panel is locally densified, with a mesh size ≤0.05H (H is the photovoltaic panel height).

[0132] Wind field simulation: Accurately simulates the complex flow of natural wind (consistent with atmospheric boundary layer characteristics) passing through the photovoltaic array, including: wind speed / turbulence changes before and after the array, inter-panel channel flow and wake interference, surface wind pressure distribution (for structural load assessment), and turbulent energy transport and heat exchange. The main governing equations are as follows:

[0133] Continuity equation:

[0134] ▽·U=0(18)

[0135] In the formula, U is the wind speed vector.

[0136] The momentum equation is:

[0137]

[0138] In the formula, t is time, and ρ a For air density, ν eff S represents the effective dynamic viscosity coefficient, and S is the source term.

[0139] The turbulent kinetic energy k equation is:

[0140]

[0141] In the formula, k is the turbulent kinetic energy, ω is the specific dissipation rate, and σ is the kinetic energy. k For the turbulent Prandtl number k, P k For the turbulence generation term, β * Model constants.

[0142] The equation for the specific dissipation rate ω is:

[0143]

[0144] In the formula, γ is the model constant, β is the model constant, and σ is the model constant. ω For the ratio of dissipation rate to Prandtl number, CD kω This is a cross-diffusion term.

[0145] Boundary conditions: Use velocity inlet and pressure outlet.

[0146] Operating condition design: Set up multi-parameter operating condition combinations, including photovoltaic panel tilt angle (covering 0°, 15°, 30°, 45°), design wind speed (covering extreme wind speeds with a 25-year return period), array spacing (2D~4D, where D is the width of the photovoltaic panel) and array arrangement (straight / staggered).

[0147] Data output:

[0148] • Extract and generate the wind pressure coefficient (C) of the photovoltaic panel surface. p Distribution cloud map: During the calculation process, the OpenFOAM solver automatically generates a cloud map named C at each output time step. p Scalar field. Where p a To calculate the air pressure at the point, p ref Far-field reference static pressure, U ref Far-field reference wind speed scalar. Extracting C from the photovoltaic panel surface. p Value, generate C p Distribution cloud map.

[0149] Establish correction coefficients for inter-board interference effects:

[0150] a. Conduct two simulations: one is an isolated photovoltaic panel, where a single photovoltaic panel is placed and its C is obtained. p The first value is the photovoltaic array, which simulates the entire array and records the position and average C of each panel. p value;

[0151] b. Calculate the interference correction coefficient η based on the position coordinates (i,j) of different points on the photovoltaic panel. ij (C of photovoltaic array and individual photovoltaic panel) p (ratio), that is in Let be the wind pressure coefficient at coordinate (i,j) in the photovoltaic array. The wind pressure coefficient at the location coordinates (i,j) of a single photovoltaic panel.

[0152] The wind pressure coefficient is converted into an equivalent wind load acting on the structural nodes, and the calculation formula is as follows:

[0153]

[0154] In the formula, F node Let N be the equivalent wind load vector at each node. e For the number of units, C p,k Let q be the wind pressure coefficient of unit k. ref For the reference point, A k Surface area of ​​unit k, n k N is the element normal vector. k (x node Unit shape function.

[0155] In this embodiment, the multiphysics coupled numerical model integration module includes: an interface development unit, a solver design unit, and a model verification and correction unit;

[0156] Interface development:

[0157] Develop a dedicated interface subroutine for finite element analysis, including DLOAD (apply load) and DISP (transfer displacement) functions.

[0158] a. DLOAD function: Dynamically loads the wave pressure field calculated by OlaFlow and the wind load field calculated by OpenFOAM onto the structural nodes. It employs a bilinear interpolation algorithm to interpolate the load data in both spatial (three-dimensional coordinates) and temporal dimensions.

[0159] b. DISP function: Feeds back the nodal displacements obtained from structural calculations to the wave field and wind field in real time to update the boundary conditions of the fluid domain.

[0160] c. For each structural node, find the nearest fluid grid points based on its spatial coordinates and use the load values ​​of these points for spatial interpolation; at the same time, perform temporal interpolation based on the fluid load data of the current time step and the next time step.

[0161] Solver Design:

[0162] An explicit-implicit hybrid solution strategy is adopted.

[0163] a. Explicit part: The fluid field (wave field and wind field) adopts explicit time progression, calculates the load of half a time step, and transfers it to the structural field.

[0164] b. Implicit Part: The structural field uses an implicit method to solve for the displacement response of a complete time step. The displacement calculated by the structural field is fed back to the fluid field through the DISP interface to update the boundary of the fluid domain, and then the fluid field performs the calculation for the next half-step.

[0165] c. Parallel computing technology: Three solvers (OlaFlow, OpenFOAM, and structure solver) run in parallel on their respective computing nodes, exchanging and synchronizing data through a coupling controller.

[0166] d. Time synchronization: All solvers use a unified time step manager to ensure that data exchange occurs at the same time.

[0167] Model validation:

[0168] The model uses a typical photovoltaic subsystem of "four piles and one support" as the verification object. It includes four piles, one support, and a set of photovoltaic panels.

[0169] a. Independent calculation: Without considering fluid-structure interaction effects, first calculate the fluid loads (waves and wind), and then statically apply the loads to the structure for solution.

[0170] b. Coupled calculation: Considering the interaction between fluid and structure, bidirectional dynamic coupling calculation is performed using the established multiphysics field coupled numerical model.

[0171] c. Model Reliability Verification: Compare the independent calculation results, coupled calculation results, and actual field monitoring data of the supporting project (including pile top displacement, pile foundation strain, photovoltaic panel vibration response, etc.) to verify the prediction accuracy of the established multiphysics coupled model. Compare the results of independent and coupled calculations, including pile top displacement response (such as maximum displacement and root mean square displacement), calculation time, energy error, etc., to verify the superiority of the established multiphysics coupled numerical model.

[0172] d. Model optimization: If the numerical model calculation results differ significantly from the monitoring results (e.g., more than 10%), adjust the parameters of the interpolation algorithm (e.g., search radius, interpolation order) and time step to reduce the error.

[0173] Example 2

[0174] The following is in conjunction with the appendix Figure 1 and attached Figure 2 The present invention provides a detailed description of the specific implementation of the multiphysics field coupling calculation system for wind and waves, seabed, pile foundation, and photovoltaic array provided by the present invention.

[0175] 1. Detailed Explanation of Implementation Steps

[0176] Step 1: Wave Element Extraction and Wave Model Construction

[0177] (1) Data acquisition and processing: Obtain no less than 10 years of historical measured wave data (including wave height, period, direction spectrum) and corresponding tidal data from the target engineering sea area.

[0178] (2) Computational domain setup and mesh generation:

[0179] A three-dimensional non-static pressure wave tank model was created in OlaFlow.

[0180] Set the calculation domain size as follows: length direction (wave propagation direction) ≥ 5 times the design wavelength (L), width direction ≥ 5 times the target pile diameter (D), height direction ≥ 2 times the design water depth (H).

[0181] A structured mesh was used, and the mesh was refined in the near-pile area (within ≤2D of the pile surface) to ensure that the mesh resolution was ≤0.1m, so as to accurately capture the pile-water interaction.

[0182] The mesh can be appropriately sparsed in areas far from the piles to improve computational efficiency.

[0183] (3) Boundary conditions and physical model settings:

[0184] Inlet boundary: Using wave velocity as the inlet, irregular wave trains are generated by inputting the JONSWAP spectral parameters fitted in step 1.

[0185] Outlet boundary: Set up a relaxation zone to eliminate waves and avoid wave reflections interfering with the flow field.

[0186] Turbulence model: The standard k-ε turbulence model is selected to simulate complex turbulence phenomena such as wave breaking and vortex shedding.

[0187] (4) Wave pressure calculation and correction:

[0188] Run the OlaFlow model to simulate the effect of waves on the pile foundation.

[0189] Key output results: Extract water pressure time history curves at different depths around the pile throughout the entire wave cycle, the diffusion process of excess pore water pressure inside the seabed soil, and the dynamic pressure distribution of impact contact surfaces of different cross sections of the variable diameter pile.

[0190] Wave force correction: Based on the pressure distribution characteristics at piles with varying diameters, the influence of sudden changes in pile diameter on wave force is analyzed, a wave force correction coefficient for the sudden change in pile diameter is established, and a correction method is formed for use in subsequent coupled calculations to correct the results of theoretical / standard formulas.

[0191] Step 2: Numerical simulation of wind load on photovoltaic array

[0192] (1) Preparation of wind element data: Collect at least 10 years of measured wind element data (wind speed, wind direction) for the target project sea area.

[0193] (2) Wind field model establishment (OpenFOAM):

[0194] A three-dimensional atmospheric boundary layer wind field model is constructed, and the computational domain must fully surround the target photovoltaic array.

[0195] Computational domain dimensions: inlet length ≥ 8 times the photovoltaic panel height (8H), outlet length ≥ 15H, width ≥ 10 times the array width, height ≥ 5H (H is the photovoltaic panel height). Ensure a blockage rate < 3%.

[0196] Mesh generation: The mesh is refined on the surface of the photovoltaic panel and in the gaps between the arrays to meet the requirements of near-wall flow simulation.

[0197] Boundary conditions:

[0198] Inlet: A velocity inlet is adopted, and the average wind speed profile, turbulence intensity profile and turbulence integral scale are set according to the measured wind data or target specifications.

[0199] Export: Pressure export is used.

[0200] Top and sides: Set to sliding wall.

[0201] Ground and photovoltaic panel surfaces: Set as non-slip walls and process using wall functions.

[0202] Turbulence model: The k-ω model is used to simulate atmospheric turbulence.

[0203] (3) Multi-condition calculation:

[0204] The design covers a variety of working conditions, including both practical and extreme scenarios:

[0205] Solar panel tilt angles: 0°, 15°, 30°, 45°.

[0206] Design wind speed: Covers normal operating wind speeds up to extreme wind speeds with a 25-year return period (refer to engineering specifications or extreme value analysis).

[0207] Array spacing: 2D~4D.

[0208] Arrangement methods: sequential or staggered.

[0209] Run OpenFOAM steady-state or transient calculations for each combination of operating conditions.

[0210] (4) Wind load database construction:

[0211] Results Extraction: Extract the wind pressure coefficient distribution cloud map of each photovoltaic panel surface under each working condition.

[0212] Interference effect analysis: By comparing the wind pressure difference between the panels at different positions in the array (front row, middle row, and rear row) and a single panel, the multi-panel interference correction coefficient is calculated.

[0213] Load transformation: Based on the quasi-static load assumption, the wind pressure coefficient distribution is multiplied by the reference dynamic pressure, and then converted into equivalent concentrated or distributed forces acting on the nodes of the finite element model of the photovoltaic panel support structure through area integration or a specified method.

[0214] Database storage: Standardized nodal wind loads under all operating conditions are stored in a standardized wind load database for use by the coupled modules.

[0215] Step 3: Integration and Solution of Multiphysics Coupled Numerical Models

[0216] (1) Preparation of finite element structural model:

[0217] A refined three-dimensional finite element model was established, including the pile foundation, seabed soil, and photovoltaic array support structure.

[0218] Set contact pairs for the pile-soil contact surface and define friction properties.

[0219] The soil section takes into account drainage conditions and initial ground stress balance.

[0220] (2) Development and implementation of coupling interfaces:

[0221] Develop user-defined subroutines for finite element analysis (DLOAD subroutines are used to define complex time-varying loads, and DISP subroutines or other field variable interfaces are used for data transfer).

[0222] Data transmission:

[0223] The time history data of pile perimeter water pressure (output of step 1) and excess pore pressure data calculated by OlaFlow are dynamically loaded into the corresponding pile element surface or soil element node in the ABAQUS model in real time through the DLOAD subroutine.

[0224] Based on the current calculation time step and the photovoltaic array attitude (tilt angle, azimuth), the corresponding nodal wind load data is retrieved and extracted from the standardized wind load database (constructed in step 2), and then loaded onto the corresponding nodes of the photovoltaic support in the ABAQUS model through the DLOAD subroutine.

[0225] (3) Coupled solution strategy:

[0226] An explicit-implicit hybrid solution strategy is adopted: explicit dynamic analysis is used for the parts involving strong nonlinearity and transient impact, while implicit integration is used for the long-period, quasi-static response parts.

[0227] By coordinating the computation process and data exchange between OlaFlow, OpenFOAM, and finite element methods through parallel computing technology, bidirectional data interaction and synchronous solution of wave field, wind field, and structural field are achieved.

[0228] (4) Model validation and parameter optimization:

[0229] Verification object: A representative "four-pile-single-support" photovoltaic subsystem model was selected as the initial verification object.

[0230] Comparative analysis: Run independent field calculations (i.e., waves, wind, and structure are calculated separately, and loads are applied according to empirical methods) and fully coupled calculations (following steps 1-3 above).

[0231] Key metrics: Compare the displacement response time history curves (especially amplitude, phase, and spectral characteristics) of key points (such as the center of the pile top) under the two calculation modes.

[0232] Parameter adjustment: Based on the comparison results, analyze and optimize the transfer function parameters in the coupling interface until the coupling model results meet the preset accuracy requirements (e.g., displacement error <5%).

[0233] Step 4: Model Validation and Application

[0234] (1) Verification using measured engineering data:

[0235] In the actual supporting project of the target offshore photovoltaic power station, deploy monitoring sensors:

[0236] Pile foundation: Install fiber optic gratings (FBG) or resistance strain gauges to measure the strain of key sections of the pile body.

[0237] Superstructure: Install accelerometers to measure the vibration response of photovoltaic panels or supports.

[0238] Environment: Simultaneously record on-site measured wave (wave height meter) and wind (anemometer) data as the model input boundary.

[0239] Prediction accuracy assessment: The environmental data measured on-site is input into the multiphysics coupling calculation system of this invention to run simulation calculations. The calculated predicted results, such as pile foundation strain and structural vibration response, are compared and analyzed with the on-site measured data from the same period to quantitatively assess the prediction accuracy of the model.

[0240] (2) Application scenario example:

[0241] Pile foundation design optimization: This system simulates the response of different pile types (such as diameter, wall thickness, and variable diameter location), different embedment depths, and different layout schemes under extreme typhoons or long-term fatigue loads, and evaluates their bearing capacity, deformation, and stability, providing a quantitative basis for optimized design.

[0242] Operation and maintenance strategy formulation: predict the stress state and cumulative damage of pile foundations under specific sea conditions (such as storm surges that occur once every few years), assess their remaining life and safety, and guide preventive maintenance or reinforcement decisions.

[0243] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A multiphysics coupling calculation system for wind, wave, seabed, pile foundation, and photovoltaic array for marine photovoltaic power plants, characterized in that, The system includes: a wave model construction module, a photovoltaic array wind load numerical simulation module, and a multi-physics field coupled numerical model integration module; The wave model construction module is used for wave element extraction and wave model construction; The photovoltaic array wind load numerical simulation module is used to perform photovoltaic array wind load numerical simulation based on extracted wave elements and constructed wave models. The multiphysics coupled numerical model integration module is used to integrate, solve, and verify multiphysics coupled numerical models based on numerical simulation structures.

2. The system according to claim 1, characterized in that, The wave model construction module includes: a data foundation unit, a model building unit, and an output parameter unit; The data base unit is used to collect measured wave spectrum data and tidal data of the engineering sea area for no less than 10 years. The model building unit is used to build a numerical model of a non-static pressure wave tank based on OlaFlow. The output parameter unit is used to calculate the time history curve of water pressure around the pile during the wave cycle, the water pressure on the seabed surface during the wave cycle, and the dynamic pressure distribution of the impact contact surface of the variable diameter pile; and to establish a wave force correction method that considers the effect of sudden changes in pile diameter.

3. The system according to claim 2, characterized in that, In the numerical model of the non-hydrostatic wave flume, the computational domain size is set as follows: length direction ≥ 5 times the design wavelength, width direction ≥ 5 times the pile diameter, and height direction ≥ 2 times the water depth; relaxation zone wave generation and wave dissipation techniques and the VOF method are used to track the free surface; and the wave breaking process is simulated by combining the k-ε turbulence model. The grid resolution in the near-pillar area is controlled to be ≤0.1m.

4. The system according to claim 2, characterized in that, The process of calculating and outputting the time history curve of the water pressure around the pile within the wave period includes: A series of pressure monitoring points were arranged on the surface of the pile foundation along the water depth direction; During the simulation, OpenFOAM's functionObject was used to record the pressure changes at each monitoring point over time; Run the simulation so that its duration covers multiple wave cycles; The pressure data of each monitoring point is extracted from the simulation results, and the hydrostatic pressure (i.e., the dynamic pressure) is subtracted to obtain the time history curve of the water pressure around the pile, i.e., the data of pressure change over time. The process of calculating the water pressure on the seabed surface during the wave period includes: A series of pressure monitoring points are set up on the seabed surface, covering the area around the pile foundation and the free seabed within a defined range; Use probes to record the pressure changes over time at pressure monitoring points; Extract the time history data of pressure on the seabed surface, and similarly subtract the hydrostatic pressure to obtain the data on the change of dynamic water pressure on the seabed surface over time; The process of calculating the dynamic pressure distribution at the impact contact surface of a variable-diameter pile includes: Define one or more monitoring surfaces in the diameter abrupt change region, and arrange pressure monitoring points inside the diameter abrupt change region and in the preset surrounding area; Record the pressure data at the monitoring points throughout the entire wave cycle; Extract the pressure distribution of the monitored surface at each time step, and analyze the spatial distribution and temporal variation of dynamic pressure, i.e., hydrodynamic pressure, in the abrupt change region. The process of establishing a wave force correction method that considers the effect of sudden changes in pile diameter includes: A correction factor is introduced based on the Morison equation to correct the drag force and inertial force terms.

5. The system according to claim 1, characterized in that, The photovoltaic array wind load numerical simulation module includes: a data collection unit, a wind field modeling unit, a working condition design unit, and a data output unit; The data collection unit is used to collect measured wind element data of the engineering sea area for no less than 10 years; The wind field modeling unit is used to construct a numerical model of the atmospheric boundary layer wind field for photovoltaic arrays based on OpenFOAM. The inlet length of the computational domain is set to be no less than 8 times the height of the photovoltaic panel. The boundary conditions are velocity inlet and pressure outlet. The operating condition design unit is used to set multi-parameter operating condition combinations, including photovoltaic panel tilt angle, design wind speed, array spacing and array arrangement. The data output unit is used to extract and generate a cloud map of the wind pressure coefficient distribution on the photovoltaic panel surface; establish a correction coefficient for the interference effect between multiple panels; convert the wind pressure coefficient into an equivalent wind load acting on the structural nodes based on the quasi-static load conversion assumption; and finally construct a standardized wind load database.

6. The system according to claim 5, characterized in that, In the numerical model of the atmospheric boundary layer wind field for photovoltaic arrays, the governing equations for wind field simulation include: Continuity equation: In the formula, U is the wind speed vector; The momentum equation is: In the formula, t is time, and ρ a For air density, ν eff The effective dynamic viscosity coefficient is given by S, where S is the source term. Here, p is the nabla operator, and p represents pressure. The turbulent kinetic energy k equation is: In the formula, k is the turbulent kinetic energy, ω is the specific dissipation rate, and σ is the kinetic energy. k For the turbulent Prandtl number k, P k For the turbulence generation term, β * Model constants, where ν is the molecular kinematic viscosity coefficient. t The turbulent eddy viscosity coefficient; The equation for the specific dissipation rate ω is: In the formula, γ is the model constant, β is the model constant, and σ is the model constant. ω For the ratio of dissipation rate to Prandtl number, CD kω This is a cross-diffusion term.

7. The system according to claim 5, characterized in that, Extract and generate the wind pressure coefficient C on the photovoltaic panel surface. p The process of creating a distribution cloud map includes: Extracting C from the surface of photovoltaic panels p value; Calculate C p Statistics include minimum, maximum, mean, and standard deviation; Based on C p Statistics, generating C p Distribution cloud map; The process of establishing the correction coefficient for inter-board interference effects includes: Two simulations were conducted, one of which involved an isolated photovoltaic panel, where a single photovoltaic panel was placed and its C value was obtained. p The first value is the photovoltaic array, which simulates the entire array and records the position and average C of each panel. p value; Based on the simulation results, the interference correction coefficient η is calculated according to the position coordinates (i,j) of different points on the photovoltaic panel. ij ; The process of converting wind pressure coefficients into equivalent wind loads acting on structural nodes and constructing a standardized wind load database includes: The wind pressure on the surface of the photovoltaic panel is converted into nodal forces in the finite element model, using the following formula: In the formula, F node Let N be the equivalent wind load vector at each node. e For the number of units, C p,k Let q be the wind pressure coefficient of unit k. ref For the reference point, A k Surface area of ​​unit k, n k N is the element normal vector. k (x node Unit shape function; Three tables are designed to form a standardized wind load database. Table 1 stores the operating condition information, Table 2 stores the load components of each node, and Table 3 stores the total force, torque, and C of each photovoltaic panel. p Statistics.

8. The system according to claim 1, characterized in that, The multiphysics coupled numerical model integration module includes: an interface development unit, a solver design unit, and a model verification and correction unit; The interface development unit is used to develop finite element-specific interface subroutines to realize the real-time and dynamic loading of wave pressure field data calculated by OlaFlow and wind load field data calculated by OpenFOAM onto the nodes of the finite element structural model; a bilinear interpolation algorithm is used to make the load data continuous in both spatial and temporal dimensions. The solver design unit is used to employ an explicit-implicit hybrid solution strategy; and to achieve bidirectional data interaction and synchronous solution between wave field, wind field and structure field through parallel computing technology; The model verification and correction unit is used to compare and analyze the differences in pile top displacement response under independent calculation and coupled calculation, taking the typical photovoltaic subsystem of "four piles-single support" as the verification object, and optimize and adjust the interface transfer function parameters.

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