A method and device for determining the full wake velocity distribution of a large wind farm

Abstract

The present invention discloses a method and device for determining the full wake velocity distribution of a large wind farm. The method comprises: dividing the three-dimensional flow domain of the wind farm into regions to generate multiple divided regions; collecting wind farm parameters and the sizes of the multiple divided regions, and determining a wall roughness correction value based on the wind farm parameters and the sizes of the multiple divided regions; meshing the three-dimensional flow domain of the wind farm to generate a three-dimensional flow domain grid; constructing a ground wall stress model based on the wall roughness correction value and the three-dimensional flow domain grid; establishing wall boundary conditions based on the ground wall stress model, and using the three-dimensional boundary conditions and the wall boundary conditions as flow domain boundary conditions; and solving a set of fluid mechanics equations based on the flow domain boundary conditions to generate full wake velocity distribution data for the large wind farm. This method achieves the purpose of determining the full wake velocity distribution of a large wind farm, effectively reducing errors and computational costs while improving wind farm simulation accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a method and device for determining the full wake velocity distribution of a large wind farm. Background Art

[0002] In recent years, with the continuous increase in the scale and number of wind farms, for wind farm groups that are relatively close to each other, the upstream wind farm will have a serious shielding effect on the downstream wind farm, increasing the fatigue load of the downstream wind farm units and seriously affecting the power generation of the downstream wind farm. Therefore, it is very important to confirm the full wake distribution of large wind farms.

[0003] Existing methods for determining the wake distribution of a wind farm include actuation methods (actuation disks, actuation lines, etc.) and wake superposition methods. The actuation method models each wind turbine in the wind farm as a power source term, which is then added to a set of fluid mechanics equations. Finally, the wake distribution of the wind farm is obtained by solving the set of equations. This method is characterized by relatively accurate calculation results, but the computational grid size is large, and the cost of using this method for calculating the full wake effect of a large wind farm is relatively high. The wake superposition method simplifies some physical assumptions to obtain an empirical formula that can reflect the wake effect of the wind farm, and then uses the empirical formula to directly calculate the wake distribution of the wind farm. This method is characterized by low cost and faster speed, but poor accuracy and cannot accurately simulate the full wake effect of the wind farm. Therefore, when determining the full wake distribution of a large wind farm, how to ensure simulation accuracy while reducing costs is a problem that technicians in this field need to solve. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing method for determining the wake distribution of wind farms, such as high cost, poor simulation accuracy, and inability to accurately simulate the full wake effect of wind farms, thereby providing a method and device for determining the full wake velocity distribution of large wind farms.

[0005] An embodiment of the present invention provides a method for determining the full wake velocity distribution of a large wind farm, comprising:

[0006] Obtaining a three-dimensional watershed of a wind farm, dividing the three-dimensional watershed of the wind farm into regions to generate a plurality of divided regions; the plurality of divided regions include a wind farm equivalent region, a transition buffer zone, and a non-wind farm region;

[0007] collecting wind farm parameters and a plurality of divided area sizes, and determining a wall roughness correction value based on the wind farm parameters and the plurality of divided area sizes;

[0008] Performing grid division on the three-dimensional watershed of the wind farm to generate a three-dimensional watershed grid;

[0009] Constructing a ground wall stress model based on the wall roughness correction value and the three-dimensional watershed grid;

[0010] Collecting three-dimensional boundary conditions, establishing wall boundary conditions based on the ground wall stress model, and using the three-dimensional boundary conditions and the wall boundary conditions as watershed boundary conditions;

[0011] A set of fluid mechanics equations is obtained, and the set of fluid mechanics equations is solved based on the boundary conditions of the flow domain to generate full wake velocity distribution data of a large wind farm.

[0012] The present invention provides a method for determining the full wake velocity distribution of a large wind farm. The method divides the three-dimensional flow area of ​​the wind farm into different areas, determines the wall roughness correction values ​​of the different areas, and then constructs a ground wall stress model based on the roughness to achieve equivalent modeling of the wind farm. This improves the wind farm simulation accuracy and effectively reduces errors and computational costs. Finally, the ground wall stress model is used to solve the fluid mechanics equations, thereby achieving the purpose of determining the full wake velocity distribution of the large wind farm and saving resources.

[0013] Optionally, dividing the three-dimensional watershed of the wind farm into regions to generate a plurality of divided regions includes:

[0014] The preset modeling area in the three-dimensional watershed of the wind farm is used as the wind farm equivalent area, and the preset transition area around the wind farm equivalent area is used as the transition buffer zone. The area in the three-dimensional watershed of the wind farm excluding the wind farm equivalent area and the transition buffer zone is used as the non-wind farm area.

[0015] Optionally, determining the wall roughness correction value based on the wind farm parameters and the sizes of the multiple divided areas includes:

[0016] determining an equivalent roughness of an equivalent area of ​​the wind farm based on the wind farm parameters;

[0017] Extracting the surface roughness of the non-wind farm area from the wind farm parameters;

[0018] The wall roughness correction value is determined based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area, and the multiple divided area sizes; wherein the multiple divided area sizes include the lengths and widths of the multiple divided areas.

[0019] Optionally, determining the equivalent roughness of the equivalent area of ​​the wind farm based on the wind farm parameters includes:

[0020] Extracting, from the wind farm parameters, a wind turbine thrust coefficient, a multiple of the wind farm flow direction length relative to the wind turbine rotor diameter, and a multiple of the wind farm span direction length relative to the wind turbine rotor diameter, and determining a friction coefficient based on the wind turbine thrust coefficient, the multiple of the wind farm flow direction length relative to the wind turbine rotor diameter, and the multiple of the wind farm span direction length relative to the wind turbine rotor diameter;

[0021] Obtaining a surface friction velocity and a von Karman constant, extracting a wind turbine hub height from the wind farm parameters, and determining a spatiotemporal average wind speed at the hub height within the wind farm based on the surface friction velocity, the von Karman constant, the surface roughness of the non-wind farm area, and the wind turbine hub height;

[0022] Extracting the wind turbine rotor diameter from the wind farm parameters, and determining the wake eddy viscosity coefficient based on the spatiotemporal average wind speed at the hub height in the wind farm, the wind turbine rotor diameter, and the wind turbine hub height;

[0023] The equivalent roughness of the wind farm equivalent area is determined based on the surface roughness of the non-wind farm area, the wind turbine rotor diameter, the wind turbine hub height, the friction coefficient and the wake eddy viscosity coefficient.

[0024] Optionally, the wall surface roughness correction value is determined based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area, and the sizes of the multiple divided areas, wherein the wall surface roughness correction value is calculated using a formula as follows:

[0025]

[0026] In the above formula, z 0,m Indicates the wall roughness correction value, z 0,hi represents the equivalent roughness of the wind farm equivalent area, z0 represents the surface roughness of the non-wind farm area, Lx_sp represents the length of the transition buffer area, Ly_sp represents the width of the transition buffer area, x1 represents the initial coordinate point of the length of the wind farm equivalent area, x2 represents the end coordinate point of the length of the wind farm equivalent area, y1 represents the initial coordinate point of the width of the wind farm equivalent area, y1 represents the end coordinate point of the width of the wind farm equivalent area, x represents the horizontal coordinate point of any position on the basin wall, and y represents the vertical coordinate point of any position on the basin wall.

[0027] Optionally, constructing a ground wall stress model based on the wall roughness correction value and the three-dimensional watershed grid includes:

[0028] Based on the three-dimensional watershed grid, an adjacent surface grid is determined, and the average velocity corresponding to the adjacent surface grid and the vertical distance from the center of the adjacent surface grid to the surface are obtained. The ground wall stress model is constructed based on the von Karman constant, the average velocity corresponding to the adjacent surface grid, the vertical distance from the center of the adjacent surface grid to the surface, and the wall roughness correction value.

[0029] Optionally, the three-dimensional boundary conditions include:

[0030] Velocity inlet boundary conditions, pressure outlet boundary conditions, periodic boundary conditions and slip boundary conditions.

[0031] In a second aspect of the present application, a device for determining the full wake velocity distribution of a large wind farm is also proposed, comprising:

[0032] A region division module is used to obtain a three-dimensional watershed of a wind farm, divide the three-dimensional watershed of the wind farm into regions, and generate a plurality of divided regions; the plurality of divided regions include a wind farm equivalent region, a transition buffer zone, and a non-wind farm region;

[0033] an acquisition module, configured to acquire wind farm parameters and a plurality of divided area sizes, and determine a wall roughness correction value based on the wind farm parameters and the plurality of divided area sizes;

[0034] A grid division module, configured to perform grid division on the three-dimensional watershed of the wind farm to generate a three-dimensional watershed grid;

[0035] A construction module, configured to construct a ground wall stress model based on the wall roughness correction value and the three-dimensional watershed grid;

[0036] An establishment module is used to collect three-dimensional boundary conditions, establish wall boundary conditions based on the ground wall stress model, and use the three-dimensional boundary conditions and the wall boundary conditions as watershed boundary conditions;

[0037] The solution module is used to obtain a set of fluid mechanics equations, solve the set of fluid mechanics equations based on the boundary conditions of the flow domain, and generate full wake velocity distribution data of a large wind farm.

[0038] Optionally, the area division module is also used to use the preset modeling area in the three-dimensional watershed of the wind farm as the wind farm equivalent area, and the preset transition area around the wind farm equivalent area as the transition buffer zone, and the area in the three-dimensional watershed of the wind farm except the wind farm equivalent area and the transition buffer zone as the non-wind farm area.

[0039] Optionally, the acquisition module includes:

[0040] A first determining submodule, configured to determine an equivalent roughness of an equivalent area of ​​a wind farm based on the wind farm parameters;

[0041] an extraction submodule, configured to extract the surface roughness of the non-wind farm area from the wind farm parameters;

[0042] The second determination submodule is used to determine the wall roughness correction value based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area and the multiple divided area sizes; wherein the multiple divided area sizes include the lengths and widths of the multiple divided areas.

[0043] Optionally, the first determining submodule includes:

[0044] a first determining unit, configured to extract, from the wind farm parameters, a wind turbine thrust coefficient, a multiple of the wind farm flow direction length relative to the wind turbine rotor diameter, and a multiple of the wind farm span direction length relative to the wind turbine rotor diameter, and determine a friction coefficient based on the wind turbine thrust coefficient, the multiple of the wind farm flow direction length relative to the wind turbine rotor diameter, and the multiple of the wind farm span direction length relative to the wind turbine rotor diameter;

[0045] a second determining unit, obtaining a surface friction velocity, extracting a wind turbine hub height from the wind farm parameters, and determining a spatiotemporal average wind speed at the hub height within the wind farm based on the surface friction velocity, the surface roughness of the non-wind farm area, and the wind turbine hub height;

[0046] a third determining unit, configured to extract the wind turbine rotor diameter from the wind farm parameters, and determine the wake eddy viscosity coefficient based on the spatiotemporal average wind speed at the hub height in the wind farm, the wind turbine rotor diameter, and the wind turbine hub height;

[0047] The fourth determining unit is configured to determine an equivalent roughness of the wind farm equivalent area based on the surface roughness of the non-wind farm area, the wind turbine rotor diameter, the wind turbine hub height, the friction coefficient, and the wake eddy viscosity coefficient.

[0048] Optionally, the calculation formula of the wall roughness correction value is as follows:

[0049]

[0050] In the above formula, z 0,m Indicates the wall roughness correction value, z 0,hirepresents the equivalent roughness of the wind farm equivalent area, z0 represents the surface roughness of the non-wind farm area, Lx_sp represents the length of the transition buffer area, Ly_sp represents the width of the transition buffer area, x1 represents the initial coordinate point of the length of the wind farm equivalent area, x2 represents the end coordinate point of the length of the wind farm equivalent area, y1 represents the initial coordinate point of the width of the wind farm equivalent area, y1 represents the end coordinate point of the width of the wind farm equivalent area, x represents the horizontal coordinate point of any position on the basin wall, and y represents the vertical coordinate point of any position on the basin wall.

[0051] Optionally, the construction module is also used to determine the adjacent surface grid based on the three-dimensional watershed grid, and obtain the average velocity corresponding to the adjacent surface grid and the vertical distance from the center of the adjacent surface grid to the surface, and construct the ground wall stress model based on the von Karman constant, the average velocity corresponding to the adjacent surface grid, the vertical distance from the center of the adjacent surface grid to the surface and the wall roughness correction value.

[0052] Optionally, the three-dimensional boundary conditions include:

[0053] Velocity inlet boundary conditions, pressure outlet boundary conditions, periodic boundary conditions and slip boundary conditions.

[0054] In the third aspect of the present application, a computer device is also proposed, comprising a processor and a memory, wherein the memory is used to store a computer program, the computer program includes a program, and the processor is configured to call the computer program to execute the method of the above-mentioned first aspect.

[0055] In a fourth aspect of the present application, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer storage medium stores a computer program, and the computer program is executed by a processor to implement the method of the first aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 This is a flow chart of a method for determining the full wake velocity distribution of a large wind farm in Example 1 of the present invention;

[0058] Figure 2 This is a flowchart of step S102 in Example 1 of the present invention;

[0059] Figure 3 This is a flowchart of step S1021 in Example 1 of the present invention;

[0060] Figure 4 This is a schematic diagram of regional division of a three-dimensional watershed in Example 1 of the present invention;

[0061] Figure 5 This is the wake velocity distribution of the wind farm at a height of 50m in Example 1 of the present invention;

[0062] Figure 6 The wake velocity distribution of the wind farm at a height of 100m in Example 1 of the present invention;

[0063] Figure 7 This is the wake velocity distribution of the wind farm at a height of 150m in Example 1 of the present invention;

[0064] Figure 8 This is a principle block diagram of a device for determining the full wake velocity distribution of a large wind farm in Example 2 of the present invention;

[0065] Figure 9 This is a principle block diagram of the acquisition module 82 in Example 2 of the present invention;

[0066] Figure 10 This is a principle block diagram of the first determination submodule 821 in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0067] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0068] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0069] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0070] Example 1

[0071] This embodiment provides a method for determining the full wake velocity distribution of a large wind farm, such as Figure 1 Shown, including:

[0072] S101 , obtaining a three-dimensional watershed of a wind farm, dividing the three-dimensional watershed of the wind farm into regions to generate multiple divided regions; the multiple divided regions include a wind farm equivalent region, a transition buffer zone, and a non-wind farm region.

[0073] Specifically, the preset modeling area in the three-dimensional watershed of the above-mentioned wind farm is used as the above-mentioned wind farm equivalent area, and the preset transition area around the above-mentioned wind farm equivalent area is used as the above-mentioned transition buffer zone, and the area in the three-dimensional watershed of the above-mentioned wind farm except the above-mentioned wind farm equivalent area and the above-mentioned transition buffer zone is used as the above-mentioned non-wind farm area.

[0074] Furthermore, a three-dimensional watershed is established according to the size of the wind farm. The length and width should be greater than the length and width of the wind farm and its tail area to be observed, and the height is the height of the atmospheric boundary layer. In the regional division, the wind farm equivalent area is the preset modeling area of ​​the actual wind farm in the three-dimensional watershed. The four parameters x1, x2, y1, and y2 are determined to represent the range of the wind farm equivalent area. The coordinates of the wind farm equivalent area include (x1, y1), (x1, y2), (x2, y1), and (x2, y2). The transition buffer area is a transition area around the wind farm equivalent area. The two parameters Lx_sp and Ly_sp are determined to represent the length and width of the transition buffer area. The selection of their values ​​must ensure a smooth transition of the surface roughness between the wind farm equivalent area and the non-wind farm area. The non-wind farm area is other areas in the three-dimensional watershed except the wind farm equivalent area and the transition area.

[0075] S102 : Collect wind farm parameters and multiple divided area sizes, and determine a wall roughness correction value based on the wind farm parameters and the multiple divided area sizes.

[0076] Specifically, wind farm parameters include the number of wind turbines in the wind farm, the arrangement of wind turbines, the diameter of wind turbine rotors D, and the thrust coefficient C of wind turbines. T , wind turbine hub height h, real ground roughness z0, etc.

[0077] S103 , gridding the three-dimensional watershed of the wind farm to generate a three-dimensional watershed grid.

[0078] Specifically, the three-dimensional watershed is divided into grids in the length, width, and height directions according to a certain grid spacing. The grid spacing in the length direction (flow direction) and the width direction (span direction) is generally 1 to 1 / 4 times the diameter of the wind wheel. The grid spacing in the height direction (vertical) is generally the smallest at the wall and increases at a certain growth rate along the height direction.

[0079] S104: Constructing a ground wall stress model based on the wall roughness correction value and the three-dimensional watershed grid.

[0080] Specifically, based on the three-dimensional watershed grid, the adjacent surface grid is determined, and the average velocity corresponding to the adjacent surface grid and the vertical distance from the center of the adjacent surface grid to the surface are obtained. Based on the von Karman constant, the average velocity corresponding to the adjacent surface grid, the vertical distance from the center of the adjacent surface grid to the surface and the wall roughness correction value, the ground wall stress model is constructed.

[0081] The expression of the above-mentioned ground wall stress model (i.e., the calculation formula of the modified surface friction velocity) is as follows:

[0082]

[0083] In the above formula, u *，m represents the corrected surface friction velocity, κ represents the von Karman constant, U L It represents the average velocity corresponding to the adjacent surface grid, and z1 represents the vertical distance from the center of the adjacent surface grid (i.e., the grid closest to the surface) to the surface.

[0084] S105 , collecting three-dimensional boundary conditions, establishing wall boundary conditions based on the ground wall stress model, and using the three-dimensional boundary conditions and the wall boundary conditions as watershed boundary conditions.

[0085] Specifically, the three-dimensional boundary conditions include: velocity inlet boundary conditions, pressure outlet boundary conditions, periodic boundary conditions and slip boundary conditions.

[0086] Furthermore, the wall boundary conditions are set based on the ground wall stress model (that is, the expression of the ground wall stress model is used as the expression of the wall boundary conditions), the basin inlet is set as the velocity inlet boundary, the pre-calculated atmospheric boundary layer turbulent wind or the wind profile with turbulent disturbance is used as the inflow, the outlet is set as the pressure outlet boundary, the two sides are set as periodic boundaries, and the top is set as the slip boundary.

[0087] S106: Obtain a group of fluid mechanics equations, solve the group of fluid mechanics equations based on the above-mentioned watershed boundary conditions, and generate full wake velocity distribution data of a large-scale wind farm.

[0088] Specifically, a set of fluid mechanics equations consisting of the incompressible Navier-Stokes equations and the continuity equation is established, and the formula is as follows:

[0089]

[0090] In the above formula, and Represent the filtered velocity in any direction of stream, vertical and span, respectively, where and Different directions, x i and x j Represents the position coordinates in any direction of the stream direction, vertical direction and span direction, where x i and x j The directions are different, t represents time, ρ represents fluid density, Indicates the corrected filter pressure, p ∞ Indicates the driving pressure, represents the sub-grid deviatoric stress calculated by the turbulence model, f i Indicates the actuating force of the wind turbine.

[0091] Furthermore, the above-mentioned basin boundary conditions are used as the boundary conditions of the fluid mechanics equations. The fluid mechanics equations are solved using the solver in the OpenFOAM platform (OpenFOAM is an open source fluid mechanics computing platform that can customize and develop flow field calculation methods according to specific research needs) to obtain information such as the velocity distribution of the wake downstream of the large wind farm.

[0092] The above-mentioned method for determining the full wake velocity distribution of a large wind farm divides the three-dimensional flow area of ​​the wind farm into different areas, determines the wall roughness correction values ​​of different areas, and then constructs a ground wall stress model based on the roughness to achieve equivalent modeling of the wind farm, improves the wind farm simulation accuracy, and effectively reduces errors and computational costs. Finally, the ground wall stress model is used to solve the above-mentioned fluid mechanics equations, thereby achieving the purpose of determining the full wake velocity distribution of the large wind farm and saving resources.

[0093] Preferably, if Figure 2 As shown, in step S102, the wall roughness correction value is determined based on the wind farm parameters and the sizes of the multiple divided areas, including:

[0094] S1021. Determine the equivalent roughness of the equivalent area of ​​the wind farm based on the above wind farm parameters.

[0095] S1022: Extract the surface roughness of the non-wind farm area from the above wind farm parameters (ie, the real ground roughness z0).

[0096] S1023. Determine the wall roughness correction value based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area, and the sizes of the multiple divided areas; wherein the sizes of the multiple divided areas include the lengths and widths of the multiple divided areas.

[0097] The calculation formula for the wall roughness correction value is as follows:

[0098]

[0099] In the above formula, z 0,m Indicates the wall roughness correction value, z 0,hi represents the equivalent roughness of the wind farm equivalent area, z0 represents the surface roughness of the non-wind farm area, Lx_sp represents the length of the transition buffer area, Ly_sp represents the width of the transition buffer area, x1 represents the initial coordinate point of the length of the wind farm equivalent area, x2 represents the end coordinate point of the length of the wind farm equivalent area, y1 represents the initial coordinate point of the width of the wind farm equivalent area, y1 represents the end coordinate point of the width of the wind farm equivalent area, x represents the horizontal coordinate point of any position on the basin wall, and y represents the vertical coordinate point of any position on the basin wall.

[0100] Preferably, if Figure 3 As shown, in step S1021, determining the equivalent roughness of the equivalent area of ​​the wind farm based on the above wind farm parameters includes:

[0101] S10211. Extract the wind turbine thrust coefficient, the multiple of the wind farm flow length relative to the wind turbine rotor diameter, and the multiple of the wind farm span length relative to the wind turbine rotor diameter from the above-mentioned wind farm parameters, and determine the friction coefficient based on the above-mentioned wind turbine thrust coefficient, the multiple of the wind farm flow length relative to the wind turbine rotor diameter, and the multiple of the wind farm span length relative to the wind turbine rotor diameter.

[0102] Wherein, the friction coefficient c ft The calculation formula is as follows:

[0103]

[0104] In the above formula, C T Represents the wind turbine thrust coefficient, s x It represents the multiple of the wind farm flow length relative to the wind turbine rotor diameter, s y It indicates the multiple of the span length of the wind farm relative to the diameter of the wind turbine rotor.

[0105] S10212. Obtain the surface friction velocity, extract the wind turbine hub height from the above wind farm parameters, and determine the spatiotemporal average wind speed at the hub height within the wind farm based on the above surface friction velocity, the surface roughness of the above non-wind farm area, and the above wind turbine hub height.

[0106] The temporal and spatial average wind speed at the hub height in the wind farm is approximately calculated using the following expression:

[0107]

[0108] In the above formula, is the temporal and spatial average wind speed at the hub height in the wind farm (i.e. the temporal and spatial average wind speed at the hub height in the wind farm), u * represents the surface friction velocity, and h represents the wind turbine hub height.

[0109] S10213. Obtain the spatiotemporal average wind speed at the hub height in the wind farm, extract the wind turbine rotor diameter and the wind turbine hub height from the above wind farm parameters, and determine the wake eddy viscosity coefficient based on the spatiotemporal average wind speed at the hub height in the wind farm, the wind turbine rotor diameter, and the wind turbine hub height.

[0110] Among them, the wake eddy viscosity coefficient The calculation formula is as follows:

[0111]

[0112] In the above formula, D represents the diameter of the wind turbine rotor.

[0113] S10214. Determine the equivalent roughness of the equivalent area of ​​the wind farm based on the surface roughness of the non-wind farm area, the wind turbine rotor diameter, the wind turbine hub height, the friction coefficient, and the wake eddy viscosity coefficient.

[0114] Among them, the equivalent roughness z of the equivalent area of ​​the wind farm is 0,hi The calculation formula is as follows:

[0115]

[0116] The following is a specific example to illustrate a method for determining the full wake velocity distribution of a large wind farm.

[0117] The specific steps are as follows:

[0118] Step 1: Extract the parameters required for calculation according to the actual situation of the wind farm.

[0119] The wind farm has a total of 126 wind turbines, which are evenly arranged in 18×7 patterns. The wind turbine spacing is 800m (meters) in the flow direction and 523m in the span direction. The wind turbine rotor diameter D=100m and the wind turbine thrust coefficient C T =1.33, wind turbine hub height h = 100m, surface roughness z0 = 0.1m.

[0120] Step 2: Establish a three-dimensional watershed containing the wind farm and divide the calculation watershed into three areas: wind farm equivalent area, transition buffer area and non-wind farm area.

[0121] like Figure 4As shown in the figure, a three-dimensional watershed is established according to the size of the wind farm: to ensure sufficient observation of the wind farm and its wake, the length of the calculation watershed is set to 30,000 m, the width is 3,400 m, and the height is 1,000 m of the atmospheric boundary layer height; the three-dimensional watershed is divided into three areas: the wind farm equivalent area, the transition buffer area, and the non-wind farm area, where x1 = 2,000, x2 = 17,000, y1 = 0, y2 = 3,400, Lx_sp = 200, and Ly_sp = 0.

[0122] Step 3: Construct the roughness correction value of each position on the wall of the three-dimensional flow domain.

[0123] Let Ly_sp = 0, that is, only the change in roughness along the flow direction is considered, the actual surface roughness z0 = 0.1, and the equivalent roughness z of the equivalent area of ​​the wind farm is calculated using the following empirical formula: 0,hi :

[0124]

[0125] Through the above calculation, we can get z 0,hi =3.533m.

[0126] Calculate the roughness correction value z at each position of the wall 0,m as follows:

[0127]

[0128] Step 4: Construct a new ground wall stress model in the SOWFA toolkit of the OpenFOAM platform to perform equivalent modeling of the wind farm.

[0129] For the SOWFA toolkit of the OpenFOAM platform, add x1, x2, y1, y2, Lx_sp, Ly_sp and z_sp to the class definition of the source program SchumannGrotzbachFvPatchField.H header file of the ground wall stress. 0,hi Seven parameter variables.

[0130] In the constructors of the SchumannGrotzbachFvPatchField.C source file for the ground wall stress, call the seven newly added variables in the class of the header file; in the member functions for calculating the ground wall stress, calculate the corrected friction velocity u *,mIn the program, select the surface average type (averageType) as local, and modify the roughness z at each position of the wall by the coordinates of the grid point (loc[facei].x and loc[facei].y), that is, x = loc[facei].x, y = loc[facei].y 0，m value, and then use the formula To calculate the corrected friction speed u *,m , where κ is the von Karman constant, U L is the average velocity of the grid layer close to the surface, and z1 is the vertical distance from the center of the grid layer close to the surface to the surface. According to the above settings, the new ground wall stress model is finally constructed to achieve equivalent modeling of the wind farm.

[0131] Step 5: Set the new ground wall stress as the wall boundary condition, set other boundary conditions and calculation parameters, and divide the three-dimensional calculation domain into grids to obtain a three-dimensional domain grid.

[0132] The new ground wall stress (i.e., the expression of the ground wall stress model) is set as the wall boundary condition, the flow domain inlet is set as the velocity inlet boundary, and the pre-calculated atmospheric boundary layer turbulent wind is used as the inflow. The inflow is calculated and obtained through the empty atmospheric boundary layer calculation domain with periodic boundaries on all sides; the outlet is set as the pressure outlet boundary, the two sides are set as periodic boundaries, and the top is set as a slip boundary.

[0133] The three-dimensional calculation domain is divided into grids according to a certain grid spacing in the length, width and height directions. The length and width directions are divided into 750 and 85 grids respectively. The grids are evenly distributed. The height direction is divided into 60 grids, and the grid growth rate is set to 2.

[0134] Step 6: Based on the settings in Step 5, establish a set of computational fluid dynamics equations and solve them using the OpenFOAM platform to obtain information such as the velocity distribution of the wake downstream of the large wind farm.

[0135] Based on the settings in step 5, a computational fluid dynamics equation system consisting of the incompressible Navier-Stokes equations and the continuity equation is established. The equation system is then solved using the solver of the SWOFA toolkit in OpenFOAM. Ultimately, information such as the velocity distribution of the wake downstream of the large wind farm is obtained.

[0136] In order to verify the accuracy of the above method, based on the present invention, two conventional methods, the actuator disk method and the wake superposition method, are used to calculate the wake distribution of the wind farm.

[0137] like Figure 5-7As shown in Figure 1, the distribution of the wake velocity (u, unit, m / s) of the wind farm at different heights using three methods is shown. The wind speed is averaged in the span direction, and the result of the wake superposition method only considers the turbine hub height of 100m. Table 1 shows the percentage of wind speed loss at 3km, 5km, and 10km downstream of the wind farm calculated using the three methods.

[0138] Table 1

[0139]

[0140]

[0141] from Figure 5-7 As can be seen from Table 1, the accuracy of the calculation results of the present invention is comparable to that of the actuator disk method, but is better than the wake superposition method. Taking the actuator disk method as a benchmark, the simulation errors of the wake superposition method and the present invention for wind speed losses at different downstream locations are shown in Table 2. It can be seen that compared with the wake superposition method, the method proposed by the present invention (i.e., the method for determining the full wake velocity distribution of a large wind farm) can significantly reduce the error in predicting the full wake effect of a large wind farm.

[0142] Table 2

[0143] Wake superposition method Method of the present invention Calculation error of wind speed loss 3km downstream 64.79％ 16.85％ Calculation error of wind speed loss 5 km downstream 71.86％ 10.48％ Calculation error of wind speed loss 10 km downstream 80.00％ 18.14％

[0144] Table 3 shows the computation time required for the present invention and the actuator disk method. It can be seen that the present invention's method reduces computation time by 11.3% compared to the actuator disk method. The above analysis demonstrates that the present invention's method can effectively reduce computational errors while conserving computational resources when calculating the full wake characteristics of large wind farms.

[0145] Table 3

[0146] Actuator disk method Method of the present invention Calculation duration 96 cores, 928 minutes 96 cores, 823 minutes

[0147] Example 2

[0148] This embodiment provides a device for determining the full wake velocity distribution of a large wind farm, such as Figure 8 Shown, including:

[0149] The region division module 81 is used to obtain a three-dimensional watershed of a wind farm, divide the three-dimensional watershed of the wind farm into regions, and generate multiple divided regions; the multiple divided regions include a wind farm equivalent region, a transition buffer zone, and a non-wind farm region.

[0150] Specifically, the preset modeling area in the three-dimensional watershed of the above-mentioned wind farm is used as the above-mentioned wind farm equivalent area, and the preset transition area around the above-mentioned wind farm equivalent area is used as the above-mentioned transition buffer zone, and the area in the three-dimensional watershed of the above-mentioned wind farm except the above-mentioned wind farm equivalent area and the above-mentioned transition buffer zone is used as the above-mentioned non-wind farm area.

[0151] Furthermore, a three-dimensional watershed is established according to the size of the wind farm. The length and width should be greater than the length and width of the wind farm and its tail area to be observed, and the height is the height of the atmospheric boundary layer. In the regional division, the wind farm equivalent area is the preset modeling area of ​​the actual wind farm in the three-dimensional watershed. The four parameters x1, x2, y1, and y2 are determined to represent the range of the wind farm equivalent area. The coordinates of the wind farm equivalent area include (x1, y1), (x1, y2), (x2, y1), and (x2, y2). The transition buffer area is a transition area around the wind farm equivalent area. The two parameters Lx_sp and Ly_sp are determined to represent the length and width of the transition buffer area. The selection of their values ​​must ensure a smooth transition of the surface roughness between the wind farm equivalent area and the non-wind farm area. The non-wind farm area is other areas in the three-dimensional watershed except the wind farm equivalent area and the transition area.

[0152] The acquisition module 82 is configured to acquire wind farm parameters and a plurality of divided area sizes, and determine a wall roughness correction value based on the wind farm parameters and the plurality of divided area sizes.

[0153] Specifically, wind farm parameters include the number of wind turbines in the wind farm, the arrangement of wind turbines, the diameter of wind turbine rotors D, and the thrust coefficient C of wind turbines. T , wind turbine hub height h, real ground roughness z0, etc.

[0154] The grid division module 83 is used to perform grid division on the three-dimensional watershed of the wind farm to generate a three-dimensional watershed grid.

[0155] Specifically, the three-dimensional watershed is divided into grids in the length, width, and height directions according to a certain grid spacing. The grid spacing in the length direction (flow direction) and the width direction (span direction) is generally 1 to 1 / 4 times the diameter of the wind wheel. The grid spacing in the height direction (vertical) is generally the smallest at the wall and increases at a certain growth rate along the height direction.

[0156] The construction module 84 is used to construct a ground wall stress model based on the wall roughness correction value and the three-dimensional flow domain grid.

[0157] Specifically, based on the three-dimensional watershed grid, an adjacent surface grid is determined, and an average velocity corresponding to the adjacent surface grid and a vertical distance from the center of the adjacent surface grid to the surface are obtained; and based on the von Karman constant, the average velocity corresponding to the adjacent surface grid, the vertical distance from the center of the adjacent surface grid to the surface, and the wall roughness correction value, the ground wall stress model is constructed;

[0158] The expression of the ground wall stress model is as follows:

[0159]

[0160] In the above formula, u *，m represents the corrected friction velocity, κ represents the von Karman constant, U L It represents the average velocity corresponding to the adjacent surface grid, and z1 represents the vertical distance from the center of the adjacent surface grid to the surface.

[0161] The establishment module 85 is used to collect three-dimensional boundary conditions, establish wall boundary conditions based on the above-mentioned ground wall stress model, and use the above-mentioned three-dimensional boundary conditions and the above-mentioned wall boundary conditions as the watershed boundary conditions.

[0162] Specifically, the three-dimensional boundary conditions include: velocity inlet boundary conditions, pressure outlet boundary conditions, periodic boundary conditions and slip boundary conditions.

[0163] Furthermore, the wall boundary conditions are set based on the ground wall stress model (that is, the expression of the ground wall stress model is used as the expression of the wall boundary conditions), the basin inlet is set as the velocity inlet boundary, the pre-calculated atmospheric boundary layer turbulent wind or the wind profile with turbulent disturbance is used as the inflow, the outlet is set as the pressure outlet boundary, the two sides are set as periodic boundaries, and the top is set as the slip boundary.

[0164] The solution module 86 is used to obtain a set of fluid mechanics equations, solve the set of fluid mechanics equations based on the above-mentioned flow domain boundary conditions, and generate full wake velocity distribution data of a large-scale wind farm.

[0165] Specifically, a set of fluid mechanics equations consisting of the incompressible Navier-Stokes equations and the continuity equation is established, and the formula is as follows:

[0166]

[0167] In the above formula, and Represent the filtered velocity in any direction of stream, vertical and span, respectively, where and Different directions, x i and x jRepresents the position coordinates in any direction of the stream direction, vertical direction and span direction, where x i and x j The directions are different, t represents time, ρ represents fluid density, Indicates the corrected filter pressure, p ∞ Indicates the driving pressure, represents the sub-grid deviatoric stress calculated by the turbulence model, f i Indicates the actuating force of the wind turbine.

[0168] Furthermore, the above-mentioned basin boundary conditions are used as the boundary conditions of the fluid mechanics equations. The fluid mechanics equations are solved using the solver in the OpenFOAM platform (OpenFOAM is an open source fluid mechanics computing platform that can customize and develop flow field calculation methods according to specific research needs) to obtain information such as the velocity distribution of the wake downstream of the large wind farm.

[0169] The above-mentioned device for determining the full wake velocity distribution of a large wind farm divides the three-dimensional flow area of ​​the wind farm into different areas, determines the wall roughness correction values ​​of different areas, and then constructs a ground wall stress model based on the roughness to achieve equivalent modeling of the wind farm, improves the wind farm simulation accuracy, and effectively reduces errors and calculation costs. Finally, the ground wall stress model is used to solve the above-mentioned fluid mechanics equations, thereby achieving the purpose of determining the full wake velocity distribution of the large wind farm and saving resources.

[0170] Preferably, if Figure 9 As shown, the acquisition module 82 includes:

[0171] The first determining submodule 821 is configured to determine the equivalent roughness of the equivalent area of ​​the wind farm based on the above wind farm parameters.

[0172] The extraction submodule 822 is configured to extract the surface roughness of the non-wind farm area (ie, the actual ground roughness z0) from the above wind farm parameters.

[0173] The second determination submodule 823 is used to determine the wall roughness correction value based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area, and the sizes of the multiple divided areas; wherein the sizes of the multiple divided areas include the lengths and widths of the multiple divided areas.

[0174] The calculation formula for the wall roughness correction value is as follows:

[0175]

[0176] In the above formula, z 0,m Indicates the wall roughness correction value, z 0,hirepresents the equivalent roughness of the wind farm equivalent area, z0 represents the surface roughness of the non-wind farm area, Lx_sp represents the length of the transition buffer area, Ly_sp represents the width of the transition buffer area, x1 represents the initial coordinate point of the length of the wind farm equivalent area, x2 represents the end coordinate point of the length of the wind farm equivalent area, y1 represents the initial coordinate point of the width of the wind farm equivalent area, y1 represents the end coordinate point of the width of the wind farm equivalent area, x represents the horizontal coordinate point of any position on the basin wall, and y represents the vertical coordinate point of any position on the basin wall.

[0177] Preferably, if Figure 10 As shown, the first determining submodule 821 includes:

[0178] The first determination unit 8211 is used to extract the wind turbine thrust coefficient, the multiple of the wind farm flow length relative to the wind turbine rotor diameter, and the multiple of the wind farm span length relative to the wind turbine rotor diameter from the above-mentioned wind farm parameters, and determine the friction coefficient based on the above-mentioned wind turbine thrust coefficient, the multiple of the wind farm flow length relative to the wind turbine rotor diameter, and the multiple of the wind farm span length relative to the wind turbine rotor diameter.

[0179] Wherein, the friction coefficient c ft The calculation formula is as follows:

[0180]

[0181] In the above formula, C T Represents the wind turbine thrust coefficient, s x It represents the multiple of the wind farm flow length relative to the wind turbine rotor diameter, s y It indicates the multiple of the span length of the wind farm relative to the diameter of the wind turbine rotor.

[0182] The second determining unit 8212 obtains the surface friction velocity, extracts the wind turbine hub height from the wind farm parameters, and determines the spatiotemporal average wind speed at the hub height in the wind farm based on the surface friction velocity, the surface roughness of the non-wind farm area, and the wind turbine hub height.

[0183] The temporal and spatial average wind speed at the hub height in the wind farm is approximately calculated using the following expression:

[0184]

[0185] In the above formula, is the temporal and spatial average wind speed at the hub height in the wind farm (i.e. the temporal and spatial average wind speed at the hub height in the wind farm), u * represents the surface friction velocity, and h represents the wind turbine hub height.

[0186] The third determination unit 8213 is used to obtain the spatiotemporal average wind speed at the hub height in the wind farm, extract the wind turbine rotor diameter and the wind turbine hub height from the above wind farm parameters, and determine the wake eddy viscosity coefficient based on the spatiotemporal average wind speed at the hub height in the wind farm, the wind turbine rotor diameter, and the wind turbine hub height.

[0187] Among them, the wake eddy viscosity coefficient The calculation formula is as follows:

[0188]

[0189] In the above formula, D represents the diameter of the wind turbine rotor.

[0190] The fourth determining unit 8214 is configured to determine an equivalent roughness of the wind farm equivalent area based on the surface roughness of the non-wind farm area, the wind turbine rotor diameter, the wind turbine hub height, the friction coefficient, and the wake eddy viscosity coefficient.

[0191] Among them, the equivalent roughness z of the equivalent area of ​​the wind farm is 0,hi The calculation formula is as follows:

[0192]

[0193] Example 3

[0194] This embodiment provides a computer device including a memory and a processor, wherein the processor is configured to read instructions stored in the memory to execute a method for determining the full wake velocity distribution of a large wind farm in any of the above method embodiments.

[0195] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0196] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0197] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0198] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0199] Example 4

[0200] This embodiment provides a computer-readable storage medium storing computer-executable instructions capable of executing a method for determining the full wake velocity distribution of a large wind farm in any of the above-described method embodiments. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk drive (HDD), or a solid-state drive (SSD); the storage medium may also include a combination of the above-described types of memory.

[0201] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for determining the full wake velocity distribution of a large wind farm, characterized in that: include: Obtaining a three-dimensional watershed of a wind farm, dividing the three-dimensional watershed of the wind farm into regions to generate a plurality of divided regions; the plurality of divided regions include a wind farm equivalent region, a transition buffer zone, and a non-wind farm region; collecting wind farm parameters and a plurality of divided area sizes, and determining a wall roughness correction value based on the wind farm parameters and the plurality of divided area sizes; Performing grid division on the three-dimensional watershed of the wind farm to generate a three-dimensional watershed grid; Constructing a ground wall stress model based on the wall roughness correction value and the three-dimensional watershed grid; Collecting three-dimensional boundary conditions, establishing wall boundary conditions based on the ground wall stress model, and using the three-dimensional boundary conditions and the wall boundary conditions as watershed boundary conditions; Obtaining a set of fluid mechanics equations, solving the set of fluid mechanics equations based on the boundary conditions of the flow domain, and generating full wake velocity distribution data of a large-scale wind farm; The determining of the wall roughness correction value based on the wind farm parameters and the sizes of the multiple divided areas includes: determining an equivalent roughness of an equivalent area of ​​the wind farm based on the wind farm parameters; Extracting the surface roughness of the non-wind farm area from the wind farm parameters; Determining the wall surface roughness correction value based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area, and the sizes of the multiple divided areas; wherein the multiple divided area sizes include the lengths and widths of the multiple divided areas; The constructing of a ground wall stress model based on the wall roughness correction value and the three-dimensional watershed grid includes: Based on the three-dimensional watershed grid, an adjacent surface grid is determined, and an average velocity corresponding to the adjacent surface grid and a vertical distance from the center of the adjacent surface grid to the surface are obtained. The ground wall stress model is constructed based on the von Karman constant, the average velocity corresponding to the adjacent surface grid, the vertical distance from the center of the adjacent surface grid to the surface, and the wall roughness correction value.

2. The method for determining the full wake velocity distribution of a large wind farm according to claim 1, characterized in that: The step of dividing the three-dimensional watershed of the wind farm into regions to generate a plurality of divided regions includes: The preset modeling area in the three-dimensional watershed of the wind farm is used as the wind farm equivalent area, and the preset transition area around the wind farm equivalent area is used as the transition buffer zone. The area in the three-dimensional watershed of the wind farm excluding the wind farm equivalent area and the transition buffer zone is used as the non-wind farm area.

3. The method for determining the full wake velocity distribution of a large wind farm according to claim 1, characterized in that: The determining the equivalent roughness of the equivalent area of ​​the wind farm based on the wind farm parameters includes: Extracting, from the wind farm parameters, a wind turbine thrust coefficient, a multiple of the wind farm flow direction length relative to the wind turbine rotor diameter, and a multiple of the wind farm span direction length relative to the wind turbine rotor diameter, and determining a friction coefficient based on the wind turbine thrust coefficient, the multiple of the wind farm flow direction length relative to the wind turbine rotor diameter, and the multiple of the wind farm span direction length relative to the wind turbine rotor diameter; Obtaining a surface friction velocity and a von Karman constant, extracting a wind turbine hub height from the wind farm parameters, and determining a spatiotemporal average wind speed at the hub height within the wind farm based on the surface friction velocity, the von Karman constant, the surface roughness of the non-wind farm area, and the wind turbine hub height; Extracting the wind turbine rotor diameter from the wind farm parameters, and determining the wake eddy viscosity coefficient based on the spatiotemporal average wind speed at the hub height in the wind farm, the wind turbine rotor diameter, and the wind turbine hub height; The equivalent roughness of the wind farm equivalent area is determined based on the surface roughness of the non-wind farm area, the wind turbine rotor diameter, the wind turbine hub height, the friction coefficient and the wake eddy viscosity coefficient.

4. A method for determining the full wake velocity distribution of a large wind farm according to any one of claims 1 to 3, characterized in that: The wall surface roughness correction value is determined based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area, and the sizes of the multiple divided areas, wherein the wall surface roughness correction value is calculated as follows: In the above formula, z 0,m Indicates the wall roughness correction value, z 0,hi represents the equivalent roughness of the wind farm equivalent area, z0 represents the surface roughness of the non-wind farm area, Lx_sp represents the length of the transition buffer area, Ly_sp represents the width of the transition buffer area, x1 represents the initial coordinate point of the length of the wind farm equivalent area, x2 represents the end coordinate point of the length of the wind farm equivalent area, y1 represents the initial coordinate point of the width of the wind farm equivalent area, y2 represents the end coordinate point of the width of the wind farm equivalent area, x represents the horizontal coordinate point of any position on the basin wall, and y represents the vertical coordinate point of any position on the basin wall.

5. The method for determining the full wake velocity distribution of a large wind farm according to claim 1, characterized in that: The three-dimensional boundary conditions include: Velocity inlet boundary conditions, pressure outlet boundary conditions, periodic boundary conditions and slip boundary conditions.

6. A device for determining the full wake velocity distribution of a large wind farm, characterized in that: include: A region division module is used to obtain a three-dimensional watershed of a wind farm, divide the three-dimensional watershed of the wind farm into regions, and generate a plurality of divided regions; the plurality of divided regions include a wind farm equivalent region, a transition buffer zone, and a non-wind farm region; an acquisition module, configured to acquire wind farm parameters and a plurality of divided area sizes, and determine a wall roughness correction value based on the wind farm parameters and the plurality of divided area sizes; A grid division module, configured to perform grid division on the three-dimensional watershed of the wind farm to generate a three-dimensional watershed grid; A construction module, configured to construct a ground wall stress model based on the wall roughness correction value and the three-dimensional watershed grid; An establishment module is used to collect three-dimensional boundary conditions, establish wall boundary conditions based on the ground wall stress model, and use the three-dimensional boundary conditions and the wall boundary conditions as watershed boundary conditions; A solution module, configured to obtain a set of fluid mechanics equations, solve the set of fluid mechanics equations based on the boundary conditions of the flow domain, and generate full wake velocity distribution data of a large wind farm; The acquisition module includes: A first determining submodule, configured to determine an equivalent roughness of an equivalent area of ​​a wind farm based on the wind farm parameters; an extraction submodule, configured to extract the surface roughness of the non-wind farm area from the wind farm parameters; a second determining submodule, configured to determine the wall roughness correction value based on the equivalent roughness of the wind farm equivalent area, the surface roughness of the non-wind farm area, and the sizes of the multiple divided areas; wherein the multiple divided area sizes include the lengths and widths of the multiple divided areas; The construction module is further used to determine the adjacent surface grid based on the three-dimensional watershed grid, and obtain the average velocity corresponding to the adjacent surface grid and the vertical distance from the center of the adjacent surface grid to the surface, and construct the ground wall stress model based on the von Karman constant, the average velocity corresponding to the adjacent surface grid, the vertical distance from the center of the adjacent surface grid to the surface and the wall roughness correction value.

7. A computer device, characterized in that: The method comprises a processor and a memory, wherein the memory is used to store a computer program, and the processor is configured to call the computer program to execute the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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