CN115563898A - Solid wall boundary numerical simulation method based on non-body-attached grid and related equipment - Google Patents
Solid wall boundary numerical simulation method based on non-body-attached grid and related equipment Download PDFInfo
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Abstract
The invention is suitable for the technical field of computational fluid mechanics boundary processing, and provides a fixed wall boundary numerical simulation method based on a non-body-attached grid and related equipment, wherein the method comprises the following steps: acquiring flow field values of a plurality of grid nodes of a non-skin grid adjacent to a solid wall boundary, wherein the grid nodes comprise first-layer grid nodes near the boundary, and the flow field values comprise first flow field values of the first-layer grid nodes; reconstructing flow field values based on a plurality of grid nodes to obtain a first boundary value flux; setting a solid wall boundary condition, combining the solid wall boundary condition with flow field values of a plurality of grid nodes, and correcting a first flow field value of a first layer of grid nodes to obtain a second flow field value of the first layer of grid nodes; and reconstructing based on the second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and simulating a solid wall boundary of the non-skin mesh by using the third boundary numerical flux. The solid wall boundary of the non-skin grid can be simulated better and more accurately.
Description
Technical Field
The invention relates to the technical field of computational fluid mechanics boundary processing, in particular to a method, a device, computer equipment and a computer readable storage medium for simulating a fixed wall boundary numerical value based on a non-body-attached grid.
Background
In numerical simulation of complex flow, two processing methods, namely a conformal grid and a non-conformal grid, exist. Although most existing commercial software employs a mesh of the skin, non-skin meshes are of increasing interest due to the relative simplicity of mesh generation. For non-conformal grids, a key problem is the processing of the boundary condition of the fixed wall, and the most common processing method at present is the immersion boundary method based on virtual points, which sets virtual grid nodes at the boundary or inside the fixed wall, and the values of the virtual grid nodes are determined by the boundary condition and the control equation together. However, for the vicinity of the boundary where the solid wall boundary is in the shape of an acute angle, a thin plate, or the like, the virtual grid node may coincide with the actual grid node, so that the setting of the virtual grid node cannot better simulate the boundary, or the virtual grid node needs to be set according to different boundaries, which may cause difficulty in processing the program.
Disclosure of Invention
The invention aims to provide a solid wall boundary numerical simulation method based on a non-skin grid, which can better simulate the solid wall boundary of the non-skin grid under the condition of not setting virtual grid nodes and avoid the problems of node setting superposition, program processing difficulty and the like caused by processing the solid wall boundary of the non-skin grid by setting the virtual grid nodes in the prior art.
In a first aspect, an embodiment of the present invention provides a fixed-wall boundary numerical simulation method based on a non-conformal mesh, including:
s1, obtaining flow field values of a plurality of grid nodes of a non-skin grid adjacent to a solid wall boundary, wherein the grid nodes comprise first-layer grid nodes near the boundary, and the flow field values comprise first flow field values of the first-layer grid nodes;
s2, reconstructing flow field values based on the grid nodes to obtain a first boundary value flux;
s3, setting a solid wall boundary condition, combining the solid wall boundary condition with the flow field values of the grid nodes, and correcting the first flow field value of the first layer of grid nodes to obtain a second flow field value of the first layer of grid nodes;
s4, reconstructing based on the second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and simulating a solid wall boundary of the non-skin grid by using the third boundary numerical flux.
Further, the reconstructing the flow field values based on the plurality of grid nodes to obtain the first boundary value flux includes:
and carrying out eccentric reconstruction on the flow field values of the grid nodes to obtain the first boundary value flux.
Further, the step of setting a solid wall boundary condition, combining the solid wall boundary condition with the flow field values of the plurality of grid nodes, and correcting the first flow field value of the first layer of grid nodes to obtain a second flow field value of the first layer of grid nodes includes:
determining the corresponding first-layer grid node on the fixed wall boundaryBoundary node of (2)So that the first layer mesh nodeAnd said border nodeThe connecting line direction of the fixed wall is the external normal direction of the fixed wall boundary;
Computing the boundary nodes by extrapolation based on the original flow field values of the plurality of grid nodesOriginal flow field value ofAnd its first and second boundary normal derivatives、;
Connecting the boundary nodeOriginal flow field value ofAnd first and second derivatives、Rotating to the external normal direction of the fixed wall boundary to obtain the boundary nodeValue of the rotating flow fieldAnd its first and second normal derivatives、;
For the boundary nodeValue of the rotating flow fieldAnd its first and second normal derivatives、Carrying out feature projection to obtain boundary nodesProjected value of the rotating flow fieldAnd its first and second normal derivatives、;
The boundary node on the fixed wall boundaryIs set to zero, in conjunction with the boundary nodeProjected value of the rotating flow fieldAdjusting the value of its rotating flow fieldAnd fixing the boundary nodes on the wall boundaryIs arranged according to a centripetal force formula and is combined with the boundary nodeFirst order normal derivative of the projected value of the rotating flow fieldAdjusting the boundary nodeFirst order normal derivative of the rotating flow field value;
Adjusted border nodeValue of the rotating flow field ofPerforming Taylor series expansion along the external normal direction of the fixed wall boundary to obtain the first layer of grid nodesValue of the rotating flow field of;
Passing through the first layer mesh nodesValue of the rotating flow fieldObtaining a second flow field value of the first layer of grid nodes
Further, the boundary node after adjustmentValue of the rotating flow fieldCarrying out Taylor series expansion along the external normal direction of the solid wall boundary to obtain the first layer of grid nodesPValue of the rotating flow fieldComprises the following steps:
Based on the boundary nodeValue of the rotating flow field ofThe first normal derivativeThe second order normal derivativeAnd said lengthhComputing the first-tier mesh nodesPValue of the rotating flow field of。
Further, the passing of the first-layer mesh nodesPValue of the rotating flow fieldObtaining the first layer grid nodeSecond flow field value ofThe method comprises the following steps:
connecting the first layer mesh nodesPValue of the rotating flow fieldRotating the outer normal direction of the fixed wall boundary to the original direction to obtain the corrected first layer of grid nodesSecond flow field value of。
Further, the reconstructing based on the second flow field value to obtain a second boundary numerical flux, and obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux includes:
based on the first layer mesh nodeCorrected second flow field valueCarrying out eccentric reconstruction to obtain the flux of the second boundary numerical value;
obtaining the first layer of grid nodesFirst flow field value before correctionA feature matrix of (a);
and calculating to obtain the third boundary value flux based on the first boundary value flux, the second boundary value flux and the feature matrix.
Further, the step of simulating the fixed-wall boundary of the non-conformal mesh by using the third boundary numerical flux includes:
and updating the flow field value of the grid node according to the flux of the third boundary value, and simulating the fixed wall boundary of the non-skin grid based on the updated flow field value of the grid node.
In a second aspect, an embodiment of the present invention provides a solid-wall boundary numerical simulation apparatus based on a non-conformal mesh, including:
the device comprises an acquisition module, a data processing module and a data processing module, wherein the acquisition module is used for acquiring flow field values of a plurality of grid nodes of a non-skin grid adjacent to a solid wall boundary, the grid nodes comprise first-layer grid nodes near the boundary, and the flow field values comprise first flow field values of the first-layer grid nodes;
the reconstruction module is used for reconstructing flow field values based on the grid nodes to obtain a first boundary value flux;
the correction module is used for setting a solid wall boundary condition, combining the solid wall boundary condition with the flow field values of the grid nodes, correcting the first flow field value of the first layer of grid nodes, and obtaining a second flow field value of the first layer of grid nodes;
and the simulation module is used for reconstructing based on the second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and simulating the solid-wall boundary of the non-skin grid by using the third boundary numerical flux.
In a third aspect, an embodiment of the present invention provides a computer device, including: the device comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein the processor executes the computer program to realize the steps in the non-skin-mesh-based solid wall boundary numerical simulation method.
In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements the steps in the non-skin mesh-based fixed wall boundary numerical simulation method.
Compared with the prior art, the embodiment of the invention mainly has the following beneficial effects: the method comprises the steps of reconstructing flow field values of a plurality of grid nodes based on non-close grid solid wall boundaries to obtain a first boundary value flux, and correcting the first flow field value of a first layer of grid nodes near the boundaries by combining solid wall boundary conditions and the flow field values of the grid nodes to obtain a corrected second flow field value; and reconstructing based on the corrected second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and finally simulating a fixed wall boundary of the non-skin grid by using the third boundary numerical flux so as to introduce boundary information into flow field numerical simulation of the non-skin grid.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention or in the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of one embodiment of a non-skin mesh-based solid wall boundary numerical simulation method of the present invention;
FIG. 2 is a schematic structural diagram of one embodiment of a one-dimensional mesh node near a non-skin mesh solid wall boundary of the present invention;
FIG. 3 is a schematic structural diagram of one embodiment of a two-dimensional mesh node near a non-conformal mesh fixed-wall boundary of the present invention;
FIG. 4 is a schematic structural diagram of an embodiment of a non-conformal mesh-based solid-wall boundary numerical simulation apparatus according to the present invention;
fig. 5 is a schematic diagram of a basic structure of a computer device according to the present invention.
In fig. 4: 401. an acquisition module 402, a reconstruction module 403, a correction module 404 and a simulation module;
in fig. 5: 500. computer device, 501, memory, 502, processor, 503, network interface.
Detailed Description
The following description provides many different embodiments, or examples, for implementing different features of the invention. The particular examples set forth below are illustrative only and are not intended to be limiting.
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.
As shown in fig. 1, fig. 1 is a flowchart of an embodiment of a non-skin-mesh-based fixed wall boundary numerical simulation method according to the present invention, where the non-skin-mesh-based fixed wall boundary numerical simulation method includes the following steps:
s1, obtaining flow field values of a plurality of grid nodes of a non-skin grid adjacent to a solid wall boundary, wherein the grid nodes comprise first-layer grid nodes near the boundary, and the flow field values comprise first flow field values of the first-layer grid nodes;
and S2, reconstructing based on the flow field values of the grid nodes to obtain a first boundary value flux.
In the embodiment of the invention, the complex fluid flow is simulated by the non-body grid, and the fluid flow control equation (or flow field control equation) can be usedThe flow field value of the grid node in the non-body-fitted grid can be obtained by solving a flow field control equation; whereinWThe flow field variable is represented by a variable,representsThe derivative with respect to time is that of,representThe derivative to space.
If the fluid flows in one-dimensional inviscid flow, the flow field variable thereofI.e. byWIs a vector consisting of density, velocity and pressure,is a feature matrix of and(ii) a If the fluid flows in two dimensions without viscosity, the flow field variable thereinI.e. byWIs prepared from the components of density,The speed of the rotation,Vector formed by velocity and pressure.
The grid nodes are composed of nodes close to the non-body grid fixed wall boundary. Specifically, if there is one-dimensional inviscid flow, the mesh nodes near the solid wall boundary of the non-skin mesh are shown in fig. 2, whereinAre the nodes of the mesh that are close to the boundary,being the first layer of mesh nodes near the boundary,are boundary nodes and do not belong to nodes in non-body meshes. The flow field value corresponding to the above-mentioned grid node is,A first flow field value for said first layer of mesh nodes; then reconstructing the flow field values to obtain a first boundary numerical flux, and specifically performing eccentric reconstruction on the flow field values of a plurality of grid nodes to obtain the first boundary numerical flux; in the field of computational fluid mechanics, numerical flux generally refers to flow field variablesWThe inflow (outflow) amount of the unit interface (i.e. the spatial variation amount of density, velocity and pressure in the flow field); further, the numerical derivative can be calculated by dividing the difference in numerical flux across the cell interface by the grid spacing.
The process of obtaining the numerical flux from the flow field value of the grid node is called reconstruction, and if the second-order method is:
wherein, the first and the second end of the pipe are connected with each other,fflow field values representing nodes of the gridW,Representing the numerical flux between the nodes of the grid(ii) a In the present invention, however, the nodes on the boundary areNo flow field value exists, so that boundary nodesFlux of nearby boundary valuesCannot adopt the formula, but can pass through the mesh node,The flow field value is obtained by an eccentric reconstruction method, and the calculation formula is as follows:
if the two-dimensional non-adhesive flow exists, the grid nodes near the solid wall boundary of the non-attached grid are shown in FIG. 3, wherein the circular arc line is the boundary, the solid nodes are the grid nodes, and the thickened grid nodes are the grid nodesIs the first layer grid node closest to the boundary, and the first flow field value of the first layer grid node is;As nodes on the boundary, in the present invention boundary nodesFor nodes not belonging to non-tessellated meshes, only boundary nodes are obtainedIs 0. Near-boundary first-layer grid nodeIn thatFirst boundary value flux in axial direction (horizontal direction in fig. 3)By usingMeaning that it is also obtained by means of the above-described off-center reconstruction, selecting a number of grid nodes, e.g. grid nodes, in the vicinity of the same grid lineP、NEtc. flow field value、And (4) calculating. The flow field values of a plurality of grid nodes nearby on the same grid line of the first layer of grid nodes nearby the boundary are adopted, the numerical flux nearby the boundary nodes is calculated in an eccentric reconstruction mode, and the first boundary numerical flux which is accurate can be obtained.
And S3, setting a solid wall boundary condition, combining the solid wall boundary condition with the flow field values of the grid nodes, and correcting the first flow field value of the first layer of grid nodes to obtain a second flow field value of the first layer of grid nodes.
Further, the flow field values of the plurality of grid nodes include an original flow field value, and the step S3 specifically includes:
determining the corresponding first layer grid node on the fixed wall boundaryBoundary node ofSo that the first layer mesh nodeAnd said border nodeThe connecting line direction of the fixed wall is the external normal direction of the fixed wall boundary;
obtaining a node close to the boundaryA plurality ofOriginal flow field values of mesh nodes, including the first layer of mesh nodesFirst flow field value of;
Computing the boundary nodes by extrapolation based on the original flow field values of the plurality of grid nodesOriginal flow field value ofAnd its first and second boundary normal derivatives、;
Connecting the boundary nodeOriginal flow field value ofAnd first and second derivativesRotating to the external normal direction of the fixed wall boundary to obtain the boundary nodeValue of the rotating flow fieldAnd its normal first and second derivatives、。
For the boundary nodeValue of the rotating flow field ofAnd its first normal derivativeCarrying out feature projection to obtain boundary nodesProjected value of the rotating flow fieldAnd its first normal derivative;
The boundary node on the fixed wall boundaryIs set to zero, in conjunction with the boundary nodeProjected value of the rotating flow fieldAdjusting the value of its rotating flow fieldAnd connecting the boundary nodes on the fixed wall boundaryNormal pressure ofThe derivatives are arranged according to a centripetal force formula, in combination with said boundary nodesFirst order normal derivative of the projected value of the rotating flow fieldAdjusting the boundary nodeFirst order normal derivative of the rotating flow field value;
The adjusted boundary nodeValue of the rotating flow field ofCarrying out Taylor series expansion along the external normal direction of the solid wall boundary to obtain the first layer of grid nodesValue of the rotating flow field;
Passing through the first layer mesh nodesValue of the rotating flow fieldObtaining the first layer grid nodesPSecond flow field value of。
In the present example, there is no adhesion for two dimensionsFlow field, first layer of grid nodes near the above boundaryPCorresponding boundary nodeFrom the boundary geometry information andPdetermining the position of the point to make the first layer of grid nodesPAnd the above boundary nodeDirection of connecting line (in)See FIG. 3) is the outer normal of the above-mentioned solid-wall boundary, i.e. the boundary nodeIs the intersection of the outer normal and the solid wall boundary. And then combining the fixed wall boundary conditions to grid nodesPThe value of (c) is corrected. Specifically, the closest border node may be obtainedA plurality of grid nodes (including nodes) in the vicinity ofPAndPsurrounding mesh nodes) of the original flow field value(including first tier mesh nodesFirst flow field value of) Based onBoundary node acquisition by extrapolationFlow field valueAnd the first and second normal derivatives thereof, and rotating to the outer normal direction of the fixed wall boundary to obtain boundary nodesValue of rotating flow fieldAnd its first and second normal derivatives、Then to、Performing characteristic projection to obtain projection valueAnd its first and second normal derivatives、(ii) a Wherein the projection matrixLAs mesh nodesOriginal flow field value ofRotate to the direction outside the boundaryAnd left feature matrices for feature projection, e.g. for the aboveRotation variable of any point in two-dimensional flow fieldWherein,Respectively a normal direction velocity and a tangential direction velocity,if the velocity of sound is sound, the corresponding left and right feature matrices are respectively,And is andis a unit matrix; recording boundary nodesValue of the rotating flow fieldRotation of the projected valueCombining the boundary condition and the projection valueCan be paired withAdjusting and correcting, and specifically calculating by the following equation system:
in the system of equations for convenienceAndall are provided with(same below), the first line of the equation set is defined by the above-mentioned wall-bounding boundary condition, i.e., the bounding wall normal velocityThe value obtained is 0, and the value obtained is,is a left feature matrixLTo (1) aiGo to the firstjElements of the column, and then the adjustedPerforming Taylor series expansion along the external normal direction of the solid wall boundary to obtain the first layer of grid nodesValue of the rotating flow field。
Further, after adjustmentCalculating the boundary nodes before Taylor series expansion along the external normal direction of the solid wall boundaryValue of rotating flow fieldFirst order normal derivative of(ii) a And then based on the above rotating flow field valueFirst and second normal derivatives,Further modifying first-level mesh nodesValue of the rotating flow field. Specifically, the above-mentioned boundary nodeFirst order normal derivative of rotating flow field valueCan be obtained by solving the following equation system
Formula of centripetal force of first line of equation set by rotary motion(pressure gradient equals centripetal force) whereinIs a boundary wall surfaceCurvature of pointA radius. The right end term in the last three rows isProjection value of point rotationThe last three elements of (a).
The nodes of the first layer of grid can be obtained by correction through Taylor series expansionValue of the rotating flow field:
Wherein the content of the first and second substances,has a mesh nodeAnd boundary nodesThe length in between. By aligning boundary nodesThe extrapolated flow field value and the first-order second-order derivative thereof rotate to be better combined with the boundary condition, and the flow field value is adjusted after feature projection, so that the first flow field value of the first-layer grid node can be better corrected, and the corrected first-layer grid node can be more accurately obtainedIn particular the first layer of mesh nodes, of the first layer of mesh nodesPValue of the rotating flow fieldRotating from the outer normal of the fixed wall boundary to the original direction to obtain the corrected first layer of grid nodesSecond flow field value of。
S4, reconstructing based on the second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and simulating a solid wall boundary of the non-skin grid by using the third boundary numerical flux.
Further, the step S4 specifically includes:
based on the first layer mesh nodeCorrected second flow field valueCarrying out eccentric reconstruction to obtain the flux of the second boundary numerical value;
and calculating to obtain the third boundary value flux based on the first boundary value flux, the second boundary value flux and the feature matrix.
In the embodiment of the invention, the first layer of grid nodes are firstly put into operationPValue of the rotating flow fieldThe external normal direction of the fixed wall boundary is rotated to the original direction to obtain the grid nodeCorrected second flow field value(ii) a Then based on the first layer of grid nodesCorrected second flow field valueAnd other grid node flow field values on the same grid line nearby, e.g. grid node in fig. 3N、MPerforming an eccentric reconstruction to obtain the second boundary numerical fluxSpecifically, the following second order reconstruction may be used:
the following third order reconstruction may also be employed:
further obtaining the first layer grid nodeFlow field value before correctionLeft feature matrix ofLFirst row ofRight feature matrixRFirst column of (1)The net isGrid nodeFlow field value before correction (i.e. original flow field value)The feature matrix of the feature projection is the same as the feature matrix of the feature projection rotated out of the boundary and backward, i.e. the rotation does not affect the feature matrix, 、 from the above feature matrixLAndRtaking a middle value; the flux of the above-mentioned third boundary valueFlux passing through said first boundary valueSecond boundary value fluxAnd feature matrix 、 And calculating to obtain:
further, the third limit value flux described above may be utilizedSimulating the solid-wall boundaries of non-skin meshes, in particularAccording to a third limit value fluxAnd updating the flow field values of the grid nodes, and simulating the fixed wall boundary of the non-skin grid based on the updated flow field values of the grid nodes. By the steps, boundary information can be added in the flow field numerical simulation of the non-conformal grid, the grid nodes for simulating the solid wall boundary of the non-conformal grid are corrected through the flow field value of the boundary point and the first-order and second-order normal derivatives of the flow field value, and the accuracy of the grid nodes is improved, so that the solid wall boundary of the non-conformal grid can be better simulated under the condition that virtual grid nodes are not required to be arranged.
In summary, in the embodiments of the present invention, a first boundary value flux is obtained based on the flow field value reconstruction of a plurality of grid nodes at a non-close grid solid-wall boundary, and then a first flow field value of a first layer of grid nodes near the boundary is corrected by combining the solid-wall boundary condition and the flow field value of the grid nodes, so as to obtain a corrected second flow field value; and reconstructing based on the corrected second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and finally simulating the fixed wall boundary of the non-attached grid by using the third boundary numerical flux so as to introduce boundary information into the numerical simulation of the non-attached grid.
It should be understood that, although the steps in the flowcharts of the figures are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and may be performed in other orders unless explicitly stated herein. Moreover, at least a portion of the steps in the flow chart of the drawings may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time or on the same device or machine, but may be performed at different times and different places, which are not necessarily performed in sequence, but may be performed alternately or alternatingly with other steps or at least a portion of the sub-steps or stages of other steps.
In a second aspect, as shown in fig. 4, fig. 4 is a schematic structural diagram of an embodiment of a non-skin-mesh-based fixed-wall boundary numerical simulation apparatus according to the present invention, and an embodiment of the present invention provides a non-skin-mesh-based fixed-wall boundary numerical simulation apparatus, including:
an obtaining module 401, configured to obtain flow field values of a plurality of grid nodes of a non-skin grid adjacent to a solid wall boundary, where the grid nodes include a first layer of grid nodes near the boundary, and the flow field values include a first flow field value of the first layer of grid nodes;
a reconstruction module 402, configured to reconstruct a flow field value based on the plurality of grid nodes to obtain a first boundary value flux;
a correcting module 403, configured to set a solid wall boundary condition, and combine the solid wall boundary condition with the flow field values of the multiple mesh nodes to correct the first flow field value of the first-layer mesh node, so as to obtain a second flow field value of the first-layer mesh node;
a simulation module 404, configured to obtain a second boundary numerical flux based on the second flow field value reconstruction, obtain a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and simulate a solid-wall boundary of the non-skin mesh by using the third boundary numerical flux.
The solid wall boundary numerical simulation device based on the non-skin-like grid provided by the embodiment of the invention can realize each implementation mode in the method embodiment of fig. 1 and corresponding beneficial effects, and is not repeated herein for avoiding repetition.
In a third aspect, an embodiment of the present invention provides a computer device, including: the device comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein the processor executes the computer program to realize the steps in the non-skin-mesh-based solid wall boundary numerical simulation method.
In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements the steps in the non-skin mesh-based fixed wall boundary numerical simulation method.
Specifically, referring to fig. 5, fig. 5 is a schematic diagram of a basic structure of a computer device according to an embodiment of the present invention. The computer device 500 includes a memory 501, a processor 502, and a network interface 503 communicatively coupled to each other via a system bus. It is noted that only a computer device 500 having components 501-503 is shown, but it is understood that not all of the shown components are required to be implemented, and that more or fewer components may be implemented instead. As will be understood by those skilled in the art, the computer device is a device capable of automatically performing numerical calculation and/or information processing according to a preset or stored instruction, and the hardware includes, but is not limited to, a microprocessor, an Application Specific Integrated Circuit (ASIC), a Programmable Gate Array (FPGA), a Digital Signal Processor (DSP), an embedded device, and the like.
The computer device can be a desktop computer, a notebook, a palm computer, a cloud server and other computing devices. The computer equipment can carry out man-machine interaction with a user through a keyboard, a mouse, a remote controller, a touch panel or voice control equipment and the like.
The memory 501 includes at least one type of readable storage medium including a flash memory, a hard disk, a multimedia card, a card type memory (e.g., SD or DX memory, etc.), a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a Read Only Memory (ROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a Programmable Read Only Memory (PROM), a magnetic memory, a magnetic disk, an optical disk, etc. In some embodiments, the storage 501 may be an internal storage unit of the computer device 500, such as a hard disk or a memory of the computer device 500. In other embodiments, the memory 501 may also be an external storage device of the computer device 500, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), or the like, provided on the computer device 500. Of course, the memory 501 may also include both internal and external memory units of the computer device 500. In this embodiment, the memory 501 is generally used for storing an operating system and various types of application software installed on the computer device 500, such as program codes of a non-conformal grid-based fixed wall boundary numerical simulation method. Further, the memory 501 may also be used to temporarily store various types of data that have been output or are to be output.
Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solutions of the present application or portions thereof that contribute to the prior art may be embodied in the form of a software product, where the computer software product is stored in a storage medium (such as a ROM/RAM, a magnetic disk, and an optical disk), and includes several instructions for enabling a terminal device (which may be a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present application.
The above description is intended to be illustrative of the preferred embodiment of the present invention and should not be taken as limiting the invention, but rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
Claims (10)
1. A solid wall boundary numerical simulation method based on non-skin grids is characterized by comprising the following steps:
s1, obtaining flow field values of a plurality of grid nodes of a non-skin grid adjacent to a solid wall boundary, wherein the grid nodes comprise first-layer grid nodes near the boundary, and the flow field values comprise first flow field values of the first-layer grid nodes;
s2, reconstructing flow field values based on the grid nodes to obtain a first boundary value flux;
s3, setting a solid wall boundary condition, combining the solid wall boundary condition with the flow field values of the grid nodes, and correcting the first flow field value of the first layer of grid nodes to obtain a second flow field value of the first layer of grid nodes;
s4, reconstructing based on the second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and simulating a solid wall boundary of the non-skin grid by using the third boundary numerical flux.
2. The method of claim 1, wherein the deriving a first boundary value flux based on the flow field value reconstruction of the plurality of grid nodes comprises:
and carrying out eccentric reconstruction on the flow field values of the grid nodes to obtain the first boundary value flux.
3. The method of claim 2, wherein the flow field values of the grid nodes comprise original flow field values, the step of setting a fixed-wall boundary condition, and combining the fixed-wall boundary condition with the flow field values of the plurality of grid nodes to modify the first flow field values of the first layer of grid nodes to obtain the second flow field values of the first layer of grid nodes comprises:
determining boundary nodes corresponding to the first layer of grid nodes on a fixed wall boundary, so that the connecting line direction of the first layer of grid nodes and the boundary nodes is the external normal direction of the fixed wall boundary;
acquiring original flow field values of a plurality of grid nodes close to the boundary node, wherein the original flow field values comprise first flow field values of the first layer of grid nodes;
calculating the original flow of the boundary node by extrapolation method based on the original flow field values of the plurality of grid nodesField values and their first and second boundary normal derivatives、;
The original flow field value and the first and second derivatives of the boundary node are obtained、Rotating to the external normal direction of the solid wall boundary to obtain the rotating flow field value of the boundary node and the first-order and second-order normal derivatives thereof、;
Rotational flow field values to the boundary nodesAnd performing characteristic projection on the first-order and second-order normal derivatives of the boundary nodes to obtain the rotating flow field projection values of the boundary nodes and the first-order and second-order normal derivatives of the boundary nodes、;
The boundary point on the fixed wall boundaryIs set to zero, in conjunction with the boundary nodeAdjusting the rotary flow field value of the projection value of the rotary flow field of the pointSetting the pressure normal derivative of the boundary node on the fixed wall boundary according to a centripetal force formula, and adjusting the first normal derivative of the rotational flow field value of the boundary node by combining the first normal derivative of the rotational flow field projection value of the boundary node;
carrying out Taylor series expansion on the adjusted rotating flow field value of the boundary node along the external normal direction of the solid wall boundary to obtain the rotating flow field value of the first layer of grid nodes;
and obtaining a second flow field value of the first-layer grid node according to the rotating flow field value of the first-layer grid node.
4. The method of claim 3, wherein the adjusted rotational flow field values of the boundary nodes are subjected to Taylor series expansion along the outer normal direction of the solid wall boundary to obtain the first layer of grid nodesPThe step of rotating the flow field value of (2) comprises:
calculating a length between the first-tier mesh node and the boundary nodeh;
The rotational flow field value, the first normal derivative, the second normal derivative, and the length based on the boundary nodeshComputing the first-tier mesh nodesPThe rotational flow field value of (a).
5. The method of claim 4, wherein said passing through said first level mesh nodesPThe obtaining of the second flow field value of the first-layer mesh node by the rotating flow field value includes:
connecting the first layer mesh nodePThe rotating flow field value is rotated to the original direction from the external normal direction of the solid wall boundary, and a second flow field value of the first layer of grid nodes after correction is obtained.
6. The method of any of claim 5, wherein reconstructing based on the second flow field values to obtain a second boundary value flux, and obtaining a third boundary value flux from the first boundary value flux and the second boundary value flux comprises:
carrying out eccentric reconstruction on the basis of the second flow field value corrected by the first layer of grid nodes to obtain a second boundary numerical flux;
acquiring a feature matrix of a first flow field value before the first layer of grid nodes are corrected;
and calculating to obtain the third boundary value flux based on the first boundary value flux, the second boundary value flux and the feature matrix.
7. The method of claim 1, wherein the step of simulating the solid wall boundary of the non-skin mesh using the third boundary numerical flux comprises:
and updating the flow field value of the grid node according to the flux of the third boundary value, and simulating the fixed wall boundary of the non-skin grid based on the updated flow field value of the grid node.
8. A solid wall boundary numerical simulation device based on non-skin-type grids is characterized by comprising:
the device comprises an acquisition module, a data processing module and a data processing module, wherein the acquisition module is used for acquiring flow field values of a plurality of grid nodes of a non-skin grid adjacent to a solid wall boundary, the grid nodes comprise first-layer grid nodes near the boundary, and the flow field values comprise first flow field values of the first-layer grid nodes;
the reconstruction module is used for reconstructing flow field values based on the grid nodes to obtain a first boundary value flux;
the correction module is used for setting a solid wall boundary condition, combining the solid wall boundary condition with the flow field values of the grid nodes, correcting the first flow field value of the first layer of grid nodes, and obtaining a second flow field value of the first layer of grid nodes;
and the simulation module is used for reconstructing based on the second flow field value to obtain a second boundary numerical flux, obtaining a third boundary numerical flux according to the first boundary numerical flux and the second boundary numerical flux, and simulating the solid-wall boundary of the non-skin mesh by using the third boundary numerical flux.
9. A computer device, comprising: memory, processor and computer program stored on the memory and executable on the processor, the processor implementing the steps in the non-skin mesh based solid wall boundary numerical simulation method according to any one of claims 1 to 7 when executing the computer program.
10. A computer-readable storage medium, having stored thereon a computer program which, when being executed by a processor, carries out the steps of the non-skin mesh-based fixed-wall boundary numerical simulation method according to any one of claims 1 to 7.
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