Basin block grid division method and device

Abstract

The invention discloses a watershed block grid division method and device, and relates to the technical field of aircraft design, and the method comprises the steps: constructing a complete entity model according to a design demand; wherein the complete entity model comprises a gap basin entity model, a body aerodynamic configuration entity model and an outer basin entity model; setting surface mesh division parameters, and performing surface mesh division on the complete solid model based on the surface mesh division parameters to obtain a surface mesh model; setting a boundary layer in an outer watershed of the surface mesh model, setting division parameters of an inner mesh of the boundary layer to perform volume mesh division, and generating a volume mesh model; and importing the volume mesh model into fluid dynamics software, and setting drainage basin communication and flow conditions for analogue simulation to obtain an aerodynamic data set. The problem that in the prior art, dividing of unstructured grids has high requirements for experience of technicians, and the calculation result is likely to be completely incredible is solved. The accuracy and the reliability of a pneumatic calculation result can be improved.

Description

Technical Field

[0001] The present application relates to the field of aircraft design technology, and in particular to a method and device for dividing a watershed into blocks and grids. Background Art

[0002] Computational grids are mainly divided into structured grids and unstructured grids. In practical applications, structured grids have smaller errors than the results of wind tunnel tests, and are therefore widely used. They can meet the flight control law design and flight requirements, and have high reliability. However, structured grids take a lot of time to divide the grids, and there is a limitation that complex shapes are difficult to divide. Therefore, unstructured grids were proposed in the 1960s. It uses the powerful computing power of computers, and a lot of work is done by computers. Compared with structured grids, it has obvious advantages and can save designers a lot of time. In addition, unstructured grids have good adaptability to models and can better divide grids in areas with complex shapes.

[0003] However, unstructured grids require a high level of technical experience. Improper grid division will lead to completely unreliable calculation results. Especially for aerodynamic shapes at gaps such as rudder surfaces, when conventional unstructured grids are used for division, there are two situations when setting the boundary layer. One is that at gaps such as rudder surfaces, the boundary layer is compressed, and the grid distribution is seriously uneven (such as Figure 3 As shown in Figure 2); second, the total height of the boundary layer is not enough (such as Figure 4 A large number of repeated calculations and comparative analyses have shown that improper boundary layer settings have a significant impact on aerodynamic calculation results, making the calculation results completely unreliable. Summary of the invention

[0004] The embodiments of the present application provide a method and device for dividing a watershed into blocks and grids, thereby solving the problem in the prior art that the division of unstructured grids requires high experience of technicians and easily leads to completely unreliable calculation results.

[0005] In the first aspect, an embodiment of the present application provides a method for block grid division of a flow domain, comprising: constructing a complete solid model according to design requirements; wherein the complete solid model includes a gap flow domain solid model, an aircraft body aerodynamic shape solid model and an outer flow domain solid model; setting surface grid division parameters, and performing surface grid division on the complete solid model based on the surface grid division parameters to obtain a surface grid model; setting a boundary layer in the outer flow domain of the surface grid model, setting the grid division parameters within the boundary layer to perform volume grid division, and generating a volume grid model; importing the volume grid model into fluid dynamics software, setting the flow domain connectivity and flow conditions for simulation, and obtaining an aerodynamic data set.

[0006] In combination with the first aspect, in a possible implementation method, the constructing of a complete solid model according to design requirements includes: constructing an aerodynamic shape solid model of an airframe based on the design requirements; determining the boundary of an outer flow domain according to the size and shape of the airframe aerodynamic shape solid model, and constructing an outer flow domain solid model of the outer flow domain; identifying the gap between the main wing and the rudder in the airframe aerodynamic shape solid model, and if the gap meets a preset gap condition, constructing the gap flow domain solid model; merging the gap flow domain solid model, the airframe aerodynamic shape solid model and the outer flow domain solid model, and performing a common node operation on the overlapping surfaces of the merged models to obtain the complete solid model.

[0007] In combination with the first aspect, in a possible implementation method, the setting of the surface mesh division parameters includes: setting the minimum size of the surface mesh so that its ratio to the minimum size of the fuselage aerodynamic shape entity model satisfies a first ratio; setting the maximum size of the outer flow domain entity model so that its ratio to the fuselage wingspan satisfies a second ratio, and the maximum size of the fuselage aerodynamic shape entity model is set to the average aerodynamic chord length; setting the growth rate of the surface mesh of the fuselage aerodynamic shape entity model and the gap flow domain entity model to a preset threshold, and the number of grid units corresponding to the minimum size in the fuselage aerodynamic shape entity model and the gap flow domain entity model is not less than the preset number of grids.

[0008] In combination with the first aspect, in a possible implementation method, after performing surface mesh division on the complete solid model based on the surface mesh division parameters, it also includes: if the divided surface mesh does not meet the quality requirements, iteratively moving the mesh nodes in the surface mesh until the surface mesh meets the quality requirements; and / or, marking the mesh nodes in the surface mesh that do not meet the quality requirements, merging the adjacent meshes involved in the mesh nodes that do not meet the quality requirements; and / or, deleting the mesh nodes in the surface mesh that do not meet the quality requirements, and re-dividing the surface mesh of the area where the mesh nodes are deleted.

[0009] In combination with the first aspect, in a possible implementation method, the setting of the division parameters of the grid in the boundary layer for volume grid division includes: determining the height of the first layer of grids and the heights of other grids in the boundary layer according to the average aerodynamic chord length; setting the growth rate of the grids in the boundary layer and the number of layers of the boundary layer; determining the size of each volume grid in the boundary layer according to the growth rate of the grids in the boundary layer, the height of the first layer of grids and the number of layers of the boundary layer, so as to perform volume grid division.

[0010] In combination with the first aspect, in a possible implementation method, determining the height of the first layer of grids and the heights of other grids in the boundary layer according to the average aerodynamic chord length includes: setting the height of the first layer of grids in the boundary layer based on the average aerodynamic chord length; determining the heights of the other grids according to the average aerodynamic chord length and the Reynolds number.

[0011] In combination with the first aspect, in a possible implementation, after generating the volume mesh model, it also includes: obtaining a mesh skewness of the volume mesh in the volume mesh model; and evaluating whether the mesh skewness satisfies a preset skewness.

[0012] In the second aspect, an embodiment of the present application provides a flow domain block grid division device, including: a construction module, which is used to construct a complete solid model according to design requirements; wherein the complete solid model includes a gap flow domain solid model, an aircraft body aerodynamic shape solid model and an outer flow domain solid model; a surface grid division module, which is used to set surface grid division parameters, and perform surface grid division on the complete solid model based on the surface grid division parameters to obtain a surface grid model; a volume grid division module, which is used to set a boundary layer in the outer flow domain of the surface grid model, set the grid division parameters in the boundary layer to perform volume grid division, and generate a volume grid model; a simulation module, which is used to import the volume grid model into fluid dynamics software, set the flow domain connectivity and flow conditions for simulation, and obtain an aerodynamic data set.

[0013] In a third aspect, an embodiment of the present application provides a device, comprising: a processor; a memory for storing processor-executable instructions; when the processor executes the executable instructions, it implements the method described in the first aspect or any possible implementation method of the first aspect.

[0014] In a fourth aspect, an embodiment of the present application provides a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium includes a medium for storing a computer program or instructions, which, when executed, enables the method described in the first aspect or any possible implementation method of the first aspect to be implemented.

[0015] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: The embodiment of the present application establishes a separate gap flow domain entity model for the gap, and by setting a boundary layer for the outer flow domain and generating a volume grid, the problems of boundary layer compression at the gap and insufficient total height of the boundary layer are avoided. Furthermore, in the subsequent fluid dynamics calculation process, by setting the flow domain connectivity, it can ensure that the connected flow domain becomes a whole flow domain for calculation. This effectively solves the problem that the division of unstructured grids in the prior art requires high experience of technicians, which easily leads to completely unreliable calculation results. This improves the accuracy and reliability of aerodynamic calculation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. 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.

[0017] Figure 1 A flow chart of a watershed block grid division method provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of a watershed block grid division device provided in an embodiment of the present application; Figure 3 A schematic diagram of the compression of the boundary layer during unstructured grid division provided in an embodiment of the present application; Figure 4 A schematic diagram of insufficient total height of the boundary layer during unstructured grid division provided in an embodiment of the present application; Figure 5 An example diagram of a solid model of the aerodynamic shape of an aircraft provided in an embodiment of the present application; Figure 6 An example diagram of an outer basin entity model provided in an embodiment of the present application; Figure 7 An example diagram of a gap flow field entity model provided in an embodiment of the present application; Figure 8 An example diagram of a complete entity model provided in an embodiment of the present application; Fig. 9 An example diagram of a surface mesh without common node operation provided in an embodiment of the present application; Fig.10 An example diagram of a surface mesh model provided in an embodiment of the present application; Fig.11 An example diagram of a grid divided by a structured grid provided in an embodiment of the present application; Fig.12 An example diagram of a grid divided by the method of the present application provided in an embodiment of the present application; Fig.13 An example diagram of filling the gap between the rudder surface and the main wing surface provided in an embodiment of the present application; Fig.14 Provided for the embodiments of this application Fig.11 Streamline diagram of the meshing method; Fig.15 Provided for the embodiments of this application Fig.11 Local streamline diagram of the meshing method; Fig.16Provided for the embodiments of this application Fig.12 Streamline diagram of the meshing method; Fig.17 Provided for the embodiments of this application Fig.12 Local streamline diagram of the meshing method; Fig.18 Provided for the embodiments of this application Figure 3 Streamline diagram of the meshing method; Fig.19 Provided for the embodiments of this application Figure 3 Local streamline diagram of the meshing method; Fig. 20 Provided for the embodiments of this application Figure 4 Streamline diagram of the meshing method; Fig.21 Provided for the embodiments of this application Figure 4 Local streamline diagram of the meshing method; Fig. 22 Provided for the embodiments of this application Fig.13 Streamline plot of the meshing method. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The following describes some of the techniques involved in the embodiments of the present application to facilitate understanding, and they should be considered as merely exemplary. Therefore, it should be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, some descriptions of well-known functions and structures are omitted in the following description.

[0020] Figure 1 1 is a flow chart of a method for dividing a watershed into blocks and grids provided in an embodiment of the present application, including steps 101 to 104. Figure 1 This is only an execution order shown in the embodiment of the present application, and does not represent the only execution order of the watershed block grid division method. In the case that the final result can be achieved, Figure 1 The steps shown may be performed in parallel or reversed.

[0021] Step 101: Construct a complete solid model according to design requirements. The complete solid model includes a gap flow domain solid model, an airframe aerodynamic shape solid model and an outer flow domain solid model. In an embodiment of the present application, based on design requirements, an airframe aerodynamic shape solid model of the aerodynamic shape is constructed. The boundary of the outer flow domain is determined according to the size and shape of the airframe aerodynamic shape solid model, and an outer flow domain solid model of the outer flow domain is constructed. The gap between the main wing and the rudder surface in the airframe aerodynamic shape solid model is identified. If the gap meets the preset gap condition, a gap flow domain solid model is constructed. The gap flow domain solid model, the airframe aerodynamic shape solid model and the outer flow domain solid model are merged, and the overlapping surfaces of the merged models are subjected to a common node operation to obtain a complete solid model.

[0022] Specifically, this application uses CFD (Computational Fluid Dynamics, computational fluid dynamics software) calculation model pre-processing software (such as CAD and other computer-aided design modeling software) to build aerodynamic shape solid models of the fuselage (including main wings, tail wings, fuselage and other components) according to design requirements, and saves them, such as Figure 5 Shown is a solid model of the aerodynamic shape of the fuselage provided in this application.

[0023] According to the size and shape of the aerodynamic shape, determine the boundary of the outer flow domain (i.e., the flow domain outside the flow domain corresponding to the gap flow domain solid model). The boundary of the outer flow domain should be large enough to include all key flow characteristics and reduce the impact of the boundary on the simulation results. Use CAD (Computer-Aided Design) software to build a three-dimensional solid model of the outer flow domain containing the aerodynamic shape, i.e., the outer flow domain solid model, to ensure that the outer flow domain solid model is seamlessly connected with the body aerodynamic shape solid model, such as Figure 6 Shown is the outer basin entity model provided by this application.

[0024] Identify the gap between the rudder surface and the main wing surface in the aerodynamic shape entity model of the fuselage. When the gap meets the preset gap conditions, use CAD software to build a three-dimensional entity model of the gap, that is, a gap flow domain entity model, to ensure that the size and shape of the gap flow domain entity model conform to the actual situation, such as Figure 7 The figure shows the gap flow domain entity model provided by the present application. The preset gap condition here is exemplarily set to be less than or equal to 0.005c, where c represents the average aerodynamic chord length.

[0025] Import the gap flow domain solid model, the body aerodynamic shape solid model and the outer flow domain solid model into the CAD software to ensure that each model is correctly positioned in space. Then merge the three models, identify all overlapping faces in the merged model, and use the common node or stitching function of the CAD software to convert these overlapping faces into common node faces for common node operations to obtain a complete solid model. The nodes on the common node faces will share the same coordinates, thereby ensuring the continuity of the complete solid model in the flow simulation, such as Figure 8 The complete entity model provided by this application is shown in FIG. If the merged model is not operated with common nodes, the meshes at the overlapping surfaces will not have common nodes, such as Fig. 9 As shown, the volume mesh cannot be generated.

[0026] Step 102: Set the surface meshing parameters, and perform surface meshing on the complete solid model based on the surface meshing parameters to obtain a surface mesh model. In an embodiment of the present application, setting the surface meshing parameters includes: setting the minimum size of the surface mesh so that it satisfies a first ratio with the minimum size of the solid model of the aerodynamic shape of the fuselage. Setting the maximum size of the external flow domain solid model so that its ratio to the wingspan of the fuselage satisfies a second ratio, and setting the maximum size of the solid model of the aerodynamic shape of the fuselage to the average aerodynamic chord length. Setting the growth rate of the surface mesh of the solid model of the aerodynamic shape of the fuselage and the gap flow domain solid model to a preset threshold, and the number of grid cells corresponding to the minimum size in the solid model of the aerodynamic shape of the fuselage and the gap flow domain solid model is not less than the preset number of grids.

[0027] Exemplarily, the first ratio is 1 / 3, that is, the minimum size of the surface grid is set to 1 / 3 of the minimum size of the body aerodynamic shape entity model. The second ratio is 10, that is, the maximum size of the outer flow domain entity model is set to 10 times the body wingspan. The preset threshold is 1.2, that is, the growth rate of the surface grid of the body aerodynamic shape entity model and the gap flow domain entity model is exemplarily set to 1.2, and the preset number of grids is exemplarily set to 3, that is, the number of grid cells corresponding to the minimum size in the body aerodynamic shape entity model and the gap flow domain entity model is not less than 3.

[0028] Based on the surface meshing parameters set above, the complete solid model is meshed to obtain a surface mesh model, such as Fig.10 As shown. In addition, evaluate whether the divided surface mesh model meets the quality requirements. If the divided surface mesh does not meet the quality requirements, iteratively move the mesh nodes in the surface mesh until the surface mesh meets the quality requirements. And / or, mark the mesh nodes in the surface mesh that do not meet the quality requirements, and merge the adjacent meshes involved in the mesh nodes that do not meet the quality requirements. And / or, delete the mesh nodes in the surface mesh that do not meet the quality requirements, and re-divide the surface mesh for the area of ​​the deleted mesh nodes. Wherein, the quality requirement is exemplarily set to the skewness of the surface mesh is less than or equal to 0.65.

[0029] Specifically, the quality of the surface mesh model is evaluated, including indicators such as mesh size, shape, and skewness. A gradient-based optimization algorithm is used to improve the shape and size of the surface mesh by adjusting the positions of the mesh nodes through multiple iterations. The quality of the surface mesh model is re-evaluated after each iteration to ensure that each adjustment is effective until the surface mesh model meets the quality requirements.

[0030] Alternatively, mark the mesh nodes of the mesh cells with skewness greater than 0.65 in the surface mesh model, merge the adjacent mesh cells with similar shapes and high skewness into a larger mesh cell, and re-evaluate the quality of the merged surface mesh model.

[0031] Alternatively, you can delete mesh nodes that cannot be improved by moving them or merging mesh elements. After deletion, regenerate the mesh in these areas using an appropriate meshing method (such as remeshing, adaptive meshing, etc.).

[0032] Step 103: Set a boundary layer in the outer flow domain of the surface mesh model, set the mesh division parameters in the boundary layer to perform volume mesh division, and generate a volume mesh model. In the embodiment of the present application, after obtaining the surface mesh model, a suitable boundary layer is set for the outer flow domain alone.

[0033] In the embodiment of the present application, the height of the first layer of grids and the heights of other grids in the boundary layer are determined according to the average aerodynamic chord length. The growth rate of the grids in the boundary layer and the number of layers of the boundary layer are set. The size of each body grid in the boundary layer is determined according to the growth rate of the grids in the boundary layer, the height of the first layer of grids, and the number of layers of the boundary layer to perform body grid division.

[0034] Specifically, the height of the first layer of grids in the boundary layer is set based on the average aerodynamic chord length; the heights of other grids are determined according to the average aerodynamic chord length and the Reynolds number. For example, the height of the first layer of grids in the boundary layer is set to c×10 -5 Those skilled in the art should realize that the height of the first layer of grid in the boundary layer should be small enough to capture the flow details in the boundary layer, but should not be too small to avoid causing the grid to be too dense and increase the computational burden.

[0035] The height of other grids is calculated as follows: .

[0036] In the formula, Indicates the height of other grids, Re represents the average aerodynamic chord length and Re represents the Reynolds number.

[0037] The growth rate of the mesh in the boundary layer is set to [1.2,2] by way of example. The growth rate determines how the size of the mesh in the boundary layer increases as the distance from the surface increases. A smaller growth rate means that the mesh is denser in the boundary layer and can capture flow details more accurately. The number of boundary layers is set to 16 by way of example to ensure that there is enough resolution in the boundary layer to capture flow features.

[0038] Use the boundary layer mesh generation tool in the CFD software to set the boundary layer volume mesh according to the above-determined partitioning parameters (height, growth rate and number of layers of the first layer of mesh). Ensure that the boundary layer volume mesh and surface mesh transition smoothly to avoid excessive gradients or gaps at the mesh junction.

[0039] In addition, the mesh skewness of the volume mesh in the volume mesh model is obtained, and it is evaluated whether the mesh skewness satisfies a preset skewness. The preset skewness here is exemplarily set to 0.95.

[0040] Step 104: Import the volume mesh model into the fluid dynamics software, set the flow domain connectivity and flow conditions for simulation, and obtain an aerodynamic data set. In an embodiment of the present application, the generated volume mesh model is imported into the CFD software, the interfaces between the connected flow domains are found and selected, and the types of these interfaces are set to Interior (interior, indicating that the interface allows the fluid to pass freely through the surface, so that the connected flow domain is equivalent to an integral flow domain). This means that these interfaces are free for fluid to pass through, thereby ensuring that the connected flow domain is treated as an integral flow domain. Set flow conditions such as pressure, temperature, and velocity, and set the angle of attack and sideslip angle of the aerodynamic shape solid model of the fuselage as well as other boundary conditions and initial conditions, and finally perform simulation.

[0041] After the calculation is completed, the aerodynamic force and aerodynamic moment that change with the angle of attack / sideslip angle are extracted, and its aerodynamic performance is analyzed to form an aerodynamic data set for the flight control law design and performance / stability analysis of the aircraft.

[0042] This application adopts an unstructured grid division method of watershed blocks to solve the problem of insufficient boundary layer height or boundary layer compression at gaps in existing unstructured grid division. Fig.11 As shown, the grid is divided into structured grids, such as Fig.12 The figure shows the grid divided by the method of the present application, and the grids of the boundary layer at the gap between the rudder surface and the main wing surface are basically consistent.

[0043] If the gap between the rudder surface and the main wing surface is filled, it can ensure that the boundary layer is set appropriately when the unstructured grid is divided, such as Fig.13 As shown, it will make the flow field at the gap inconsistent with the actual situation, resulting in errors in the calculation results such as too large lift and too small drag.

[0044] like Fig.14 and Fig.15 Shown Fig.11 The streamline diagram of the meshing method in (structured grid) shows that the height of the boundary layer is set appropriately, and boundary layer compression occurs in the gap between the rudder surface and the main wing. Fig.16 and Fig.17 Shown Fig.12 Streamline diagram of the grid partitioning method in (unstructured grid for watershed partitioning in this application). Fig.18 and Fig.19 Shown Figure 3 The streamline diagram of the meshing method in (unstructured grid, boundary layer compression) shows obvious curvature of the streamlines at the gaps, which affects the aerodynamic calculation results. Fig. 20 and Fig.21 Shown Figure 4 The streamline diagram of the meshing method in (unstructured grid, insufficient total height of the boundary layer) shows that the height of the boundary layer is less than the calculated result. Fig. 22 Shown Fig.13 The calculation results of the meshing method in (unstructured grid, gap filling) show that the gap filling streamline diagram has no streamlines at the gaps, which is inconsistent with the actual flow.

[0045] As shown below, Table 1, Table 3, and Table 5 are the aerodynamic calculation results of the aerodynamic shape of the same aircraft using different grid division methods (except for the different grid division methods, other calculation settings are exactly the same). Table 1 is the drag coefficient at 0°, 2°, and 4° angles of attack, Table 3 is the lift coefficient at 0°, 2°, and 4° angles of attack, and Table 5 is the pitch moment coefficient at 0°, 2°, and 4° angles of attack. Fig.12 , Figure 3 , Figure 4 , Fig.13 The unstructured grid shown is Fig.11 Relative error of the calculation results for the structured grid shown.

[0046] The relative error is calculated as follows: Relative error = (unstructured grid - structured grid) / structured grid. The calculation results are shown in Table 2, Table 4, and Table 6 respectively.

[0047] Table 1 Resistance coefficient table

[0048] Table 2 Relative error of drag coefficient

[0049] Table 3 Lift coefficient table

[0050] Table 4 Lift coefficient relative error table

[0051] Table 5 Pitch moment table

[0052] Table 6 Pitch moment relative error

[0053] Based on the above analysis, the calculation results of the basin block unstructured grid in this application have a small relative error with the structured grid calculation results, high reliability, and meet the needs of engineering design.

[0054] Although the present application provides method operation steps as described in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in this embodiment is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in sequence or in parallel according to the method shown in this embodiment or the accompanying drawings (for example, in a parallel processor or multi-threaded processing environment).

[0055] like Figure 2 As shown, the embodiment of the present application also provides a watershed block grid division device 200. The device comprises: a construction module 201, a surface grid division module 202, a volume grid division module 203 and a simulation module 204, as follows.

[0056] The construction module 201 is used to construct a complete entity model according to design requirements, wherein the complete entity model includes a gap flow domain entity model, a body aerodynamic shape entity model and an outer flow domain entity model.

[0057] The surface meshing module 202 is used to set surface meshing parameters, and perform surface meshing on the complete solid model based on the surface meshing parameters to obtain a surface mesh model.

[0058] The volume mesh division module 203 is used to set a boundary layer in the outer flow domain of the surface mesh model, set the mesh division parameters in the boundary layer to perform volume mesh division, and generate a volume mesh model.

[0059] The simulation module 204 is used to import the volume grid model into the fluid dynamics software, set the flow domain connectivity and flow conditions for simulation, and obtain the aerodynamic data set.

[0060] Some modules in the apparatus described in the present application can be described in the general context of computer executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0061] The devices or modules described in the above application embodiments can be implemented by computer chips or entities, or by products with certain functions. For the convenience of description, the above devices are described in various modules according to their functions. When implementing the embodiments of the present application, the functions of each module can be implemented in the same or multiple software and / or hardware. Of course, the module that implements a certain function can also be implemented by combining multiple sub-modules or sub-units.

[0062] The methods, devices or modules described in this application can be implemented in the form of computer-readable program codes. The controller can be implemented in any appropriate manner. For example, the controller can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program codes (such as software or firmware) that can be executed by the (micro)processor, logic gates, switches, application-specific integrated circuits (English: Application Specific Integrated Circuit; Abbreviation: ASIC), programmable logic controllers and embedded microcontrollers. Examples of controllers include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicone Labs C8051F320. The memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program codes, the controller can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, this controller can be considered as a hardware component, and the devices included in it for implementing various functions can also be regarded as structures within the hardware component. Or even, the means for realizing various functions may be regarded as both a software module for realizing the method and a structure within a hardware component.

[0063] An embodiment of the present application further provides a device, comprising: a processor; a memory for storing processor executable instructions; when the processor executes the executable instructions, the method described in the embodiment of the present application is implemented.

[0064] The embodiments of the present application also provide a non-volatile computer-readable storage medium on which a computer program or instruction is stored. When the computer program or instruction is executed, the method described in the embodiments of the present application is implemented.

[0065] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist independently, or two or more modules may be integrated into one module.

[0066] The above storage media include but are not limited to random access memory (RAM), read-only memory (ROM), cache, hard disk drive (HDD) or memory card. The memory can be used to store computer program instructions.

[0067] It can be seen from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus necessary hardware. Based on this understanding, the technical solution of the present application can be essentially or partly reflected in the prior art in the form of a software product, or it can be reflected in the implementation process of data migration. The computer software product can be stored in a storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0068] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. All or part of this application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld devices or portable devices, tablet devices, mobile communication terminals, multi-processor systems, microprocessor-based systems, programmable electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc.

[0069] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A method for dividing a watershed into blocks and grids, characterized in that: include: Constructing a complete entity model according to design requirements; wherein the complete entity model includes a gap flow domain entity model, an airframe aerodynamic shape entity model and an outer flow domain entity model; Setting surface meshing parameters, and performing surface meshing on the complete solid model based on the surface meshing parameters to obtain a surface mesh model; Setting a boundary layer in the outer flow domain of the surface grid model, setting the grid division parameters in the boundary layer to perform volume grid division, and generating a volume grid model; The volume grid model is imported into fluid dynamics software, and flow domain connectivity and flow conditions are set for simulation to obtain an aerodynamic data set.

2. The method according to claim 1, characterized in that The complete entity model is constructed according to the design requirements, including: Based on the design requirements, construct a solid model of the aerodynamic shape of the fuselage; Determine the boundary of the outer flow domain according to the size and shape of the aerodynamic shape entity model of the aircraft body, and construct the outer flow domain entity model of the outer flow domain; Identify the gap between the main wing surface and the control surface in the aerodynamic shape entity model of the aircraft body, and if the gap meets the preset gap condition, construct the gap flow domain entity model; The gap flow domain entity model, the body aerodynamic shape entity model and the outer flow domain entity model are merged, and a common node operation is performed on the overlapping surfaces of the merged models to obtain the complete entity model.

3. The method according to claim 1, characterized in that The setting of the surface meshing parameters includes: Setting a minimum size of the surface mesh so that it satisfies a first ratio with a minimum size of the solid model of the aerodynamic shape of the aircraft body; The maximum size of the outer flow domain entity model is set so that the ratio of the maximum size of the outer flow domain entity model to the fuselage wingspan satisfies the second ratio, and the maximum size of the fuselage aerodynamic shape entity model is set to the average aerodynamic chord length; The growth rate of the surface mesh of the airframe aerodynamic shape entity model and the gap flow domain entity model is set to a preset threshold, and the number of mesh units corresponding to the minimum size in the airframe aerodynamic shape entity model and the gap flow domain entity model is not less than the preset number of mesh units.

4. The method according to claim 1, characterized in that After performing surface meshing on the complete solid model based on the surface meshing parameters, the method further includes: If the divided surface mesh does not meet the quality requirements, the mesh nodes in the surface mesh are iteratively moved until the surface mesh meets the quality requirements; and / or, marking mesh nodes in the surface mesh that do not meet the quality requirements, and merging adjacent meshes involved in the mesh nodes that do not meet the quality requirements; And / or, mesh nodes that do not meet quality requirements in the surface mesh are deleted, and the surface mesh is re-divided in the area where the mesh nodes are deleted.

5. The method according to claim 3, characterized in that: The step of setting the mesh partitioning parameters in the boundary layer to perform volume mesh partitioning includes: Determine the height of the first layer of grids and the heights of other grids in the boundary layer according to the average aerodynamic chord length; Setting the growth rate of the grid in the boundary layer and the number of layers of the boundary layer; The size of each volume grid in the boundary layer is determined according to the growth rate of the grid in the boundary layer, the height of the first layer of grids and the number of layers of the boundary layer, so as to perform volume grid division.

6. The method according to claim 5, characterized in that Determining the height of the first layer of grids and the heights of other grids in the boundary layer according to the average aerodynamic chord length includes: Setting the height of the first layer of grids in the boundary layer based on the average aerodynamic chord length; The heights of the other grids are determined according to the average aerodynamic chord length and the Reynolds number.

7. The method according to claim 1, characterized in that After the volume mesh model is generated, the method further includes: Get the mesh skewness of the volume mesh in the volume mesh model; Evaluate whether the grid skewness satisfies a preset skewness.

8. A watershed grid division device, characterized in that: include: A construction module is used to construct a complete entity model according to design requirements; wherein the complete entity model includes a gap flow domain entity model, a body aerodynamic shape entity model and an outer flow domain entity model; A surface meshing module, used for setting surface meshing parameters, and performing surface meshing on the complete solid model based on the surface meshing parameters to obtain a surface mesh model; A volume mesh division module, used for setting a boundary layer in the outer flow domain of the surface mesh model, setting the mesh division parameters in the boundary layer to perform volume mesh division, and generating a volume mesh model; The simulation module is used to import the volume grid model into the fluid dynamics software, set the flow domain connectivity and flow conditions for simulation, and obtain the aerodynamic data set.

9. A device for executing a watershed block grid partitioning method, characterized in that: include: processor; a memory for storing processor-executable instructions; When the processor executes the executable instructions, the method according to any one of claims 1 to 7 is implemented.

10. A non-volatile computer-readable storage medium, characterized in that: The device comprises a computer program or an instruction for storing the computer program or the instruction, which, when executed, enables the method according to any one of claims 1 to 7 to be implemented.

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