CN109783965B - Automatic block encryption method for structural grid - Google Patents
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Abstract
The invention discloses an automatic block encryption method for a structural grid, which comprises the following steps: firstly, grouping grid blocks of an original structural grid according to boundary conditions of the original structural grid; secondly, according to the encryption coefficient, on the premise of not changing the space topology of the original structural grid, carrying out encryption reconstruction on each grouped grid block; step three, the groups after the encryption reconstruction are reassembled, and an encryption reconstruction grid is obtained by updating boundary conditions among different groups; and step four, carrying out various checks on the encryption reconstruction grid, and outputting the encryption reconstruction grid and boundary conditions thereof. The invention automatically groups and encrypts and reconstructs according to the boundary condition of the original structural grid and automatically outputs the encrypted and reconstructed grid and the boundary condition thereof, thereby realizing the automatic block encryption of the structural grid, completely needing no manual intervention, having high efficiency and stability and putting an end to errors possibly introduced by manual operation.
Description
Technical Field
The invention relates to an automatic block encryption method for a structural grid.
Background
At present, due to excellent computational efficiency and reliable computational accuracy, the structural mesh method is still in the mainstream in computational Fluid dynamics cfd (computational Fluid dynamics). However, the generation of the computational grid in the structural grid method is a very labor-consuming and time-consuming work, and when the local flow field needs to adjust the simulation strategy and the grid density needs to be increased or decreased in the numerical simulation process, a user needs to perform a lot of manual operations and have sufficient experience to obtain a satisfactory effect, and at this time, the problem of human resource consumption is more prominent. The classic algorithm of the CFD includes technologies such as an overlapped grid (overlarset grid) and a stitched grid (patched grid), which can partially encrypt a structural grid to solve the problem that the conventional docking grid is difficult to solve, but these methods all require a user to manually reconstruct a spatial grid topology, perform interface projection again, and divide a computational grid, so that the workload is large, and the work efficiency of such research is greatly reduced.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the existing problems, the method for automatically blocking and encrypting the structural grid is provided, can be used for all structural grid forms such as butt-joint grids, overlapped grids, splicing grids and the like, does not need any manual intervention, and can greatly reduce the time and labor cost in the grid generation process.
The technical scheme adopted by the invention is as follows:
an automatic blocking encryption method for a structural grid comprises the following steps:
firstly, grouping grid blocks of an original structural grid according to boundary conditions of the original structural grid;
secondly, according to the encryption coefficient, on the premise of not changing the space topology of the original structural grid, carrying out encryption reconstruction on each grouped grid block;
step three, the groups after the encryption reconstruction are reassembled, and an encryption reconstruction grid is obtained by updating boundary conditions among different groups;
and step four, carrying out various checks on the encryption reconstruction grid, and outputting the encryption reconstruction grid and boundary conditions thereof.
Further, the method for grouping the grid blocks of the original structural grid according to the boundary condition of the original structural grid in the first step is as follows:
step 1.1, reading the space point coordinates and boundary conditions of the original structural grid;
and step 1.2, automatically grouping the grid blocks of the original structural grid from inside to outside according to boundary conditions of the grid blocks.
Further, the grouping of the original structural mesh includes: an object plane boundary group, a far field boundary group and an intermediate zone group;
automatically grouping by adopting a method for searching boundary conditions of the original structural grid:
the grid blocks containing the wall surface boundaries are coded into an object surface boundary group;
compiling grid blocks containing far-field boundaries into a far-field boundary group;
and encoding the grid blocks of the original structural grid except the object plane boundary group and the far field boundary group into the middle area group.
Further, in the second step, on the premise that the spatial topology of the original structural grid is not changed according to the encryption coefficient, the method for performing encryption reconstruction on each grouped grid block comprises the following steps:
step 2.1, according to the encryption coefficient, adopting a structural grid reconstruction method to encrypt and redistribute the ridge lines of each grouped grid block on the premise of not changing the space topology of the original structural grid;
step 2.2, according to the encryption coefficient, 6 surfaces of each grouped grid block are encrypted and redistributed, and the 6 surfaces of the grid blocks are projected according to the requirement;
and 2.3, reconstructing the grid blocks of each group by adopting an overrun interpolation method.
Further, the encryption coefficient of the lattice block of each packet is given by a user according to a specific calculation state.
Further, the third step is that the method for reassembling the packets after the encryption reconstruction and obtaining the encryption reconstruction grid by updating the boundary conditions between different packets comprises:
step 3.1, sequentially refreshing three direction indexes of the grid blocks of each group according to the encryption coefficients;
and 3.2, judging whether the butted grid blocks of the grid blocks belong to the same group with the grid blocks according to the grid butting relation contained in the boundary condition of the grid blocks, if the butted grid blocks belong to the same group, continuously keeping the butted grid blocks as the butted boundary, and if the butted grid blocks do not belong to the same group, replacing the butted boundary of the grid blocks and the butted grid blocks with the butted boundary, and endowing a new butted boundary condition.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
the invention automatically groups and encrypts and reconstructs according to the boundary condition of the original structural grid and automatically outputs the encrypted and reconstructed grid and the boundary condition thereof, thereby realizing the automatic block encryption of the structural grid, completely needing no manual intervention, having high efficiency and stability and putting an end to errors possibly introduced by manual operation. Meanwhile, the method is also suitable for some calculation states which need local encryption due to irregular shapes, such as vortex generators and other small-scale components and wing tip vortexes, edge vortex and other complex flow field phenomena, and users only need to specify the grid blocks which need to be encrypted. Meanwhile, the method has no limitation on the specific grid form, so that the method can be generally applied to all forms of the structural grid (butt-joint grid, splicing grid and overlapping grid), thereby having wider application range.
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 will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a flow chart of the method for automatic block encryption of a structural grid according to the present invention.
FIG. 2 is a diagram illustrating automatic grouping of primitive structural grids according to the present invention.
Fig. 3 is a schematic diagram of the reassembly of the encrypted reconstruction grid of the present invention.
Fig. 4 is a partial detail diagram of the encryption reconstruction grid according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
The features and properties of the present invention are described in further detail below with reference to examples.
Example 1
The method for automatically blocking and encrypting the structural grid provided by the embodiment is implemented based on a boundary condition format (compatible pointwise and ICEM) of mainstream business software and a splicing grid computing method widely applied in CFD, and as shown in fig. 1, the method specifically includes:
firstly, grouping grid blocks of an original structural grid according to boundary conditions of the original structural grid:
step 1.1, reading the space point coordinates and boundary conditions of the original structural grid; the information of the boundary grid blocks inside and outside the flow field can be obtained by utilizing the boundary file of the original structural grid, so that the space point coordinates and the boundary conditions of the original structural grid are obtained;
and step 1.2, automatically grouping the grid blocks of the original structural grid from inside to outside according to boundary conditions of the grid blocks.
Grouping of the original structural mesh, comprising: an object plane boundary group, a far field boundary group and an intermediate zone group; specifically, the method of searching the boundary condition of the original structural grid can be adopted to automatically perform grouping:
the grid blocks containing the wall surface boundaries are coded into an object surface boundary group;
encoding the grid blocks containing the far-field boundaries into a far-field boundary group;
and encoding the grid blocks of the original structural grid except the object plane boundary group and the far field boundary group into the middle area group.
The grid blocks of the original structural grid may also be grouped according to user-specified blocks.
Secondly, according to the encryption coefficient, on the premise of not changing the space topology of the original structural grid, carrying out encryption reconstruction on each grouped grid block:
step 2.1, according to the encryption coefficient, adopting a structural grid reconstruction method to encrypt and redistribute the ridge lines of each grouped grid block on the premise of not changing the space topology of the original structural grid;
step 2.2, according to the encryption coefficient, carrying out encryption redistribution on 6 surfaces of each grouped grid block;
it is worth noting that in the above process, 6 surfaces of the grid block can be projected as required, so as to ensure that the ridge or the surface is encrypted and reconstructed on the premise of not changing the spatial topology of the original structural grid; the invention adopts a fuzzy normal projection method to carry out object plane or interface projection; the fuzzy normal projection method adopts the average normal of one area of the projection area as the projection direction of one object plane unit of the grid block, and when the projection object plane unit moves along two directions, the projection area also translates slightly, so that even if the curvature change of the object plane unit is large, the projection direction can not change violently, the fuzzy normal projection method has strong adaptability to various irregular object planes, and the process of object plane projection is more accurate and reliable.
And 2.3, reconstructing the grid blocks of each group by adopting a TransFinite Interpolation (TFI).
The encryption coefficient of each grouped lattice block described above is given by the user according to a specific calculation state.
Step three, reassembling the encrypted and reconstructed packets, and obtaining an encrypted and reconstructed grid by updating boundary conditions among different packets:
step 3.1, sequentially refreshing three direction indexes of the grid blocks of each group according to the encryption coefficient; after different groups of grid blocks are encrypted differently according to the encryption coefficients, the number of the grid blocks in three directions changes, so that three direction indexes (namely the number of grid block points in three directions) of each group of grid blocks are converted into new encrypted grid block points.
Step 3.2, according to the grid butt joint relation contained in the boundary condition of the grid block, judging whether the butt joint grid block of the grid block belongs to the same group with the grid block, if the butt joint grid block belongs to the same group, continuously keeping the butt joint boundary, if the butt joint grid block does not belong to the same group, replacing the butt joint boundary of the grid block and the butt joint grid block thereof with a splicing boundary, and endowing a new splicing boundary condition, thereby realizing the automatic conversion of the butt joint boundary into the traditional splicing boundary;
and step four, carrying out various checks on the encryption reconstruction grid, and outputting the encryption reconstruction grid and boundary conditions thereof.
The following describes the method for automatically blocking and encrypting the structural grid in this embodiment by taking a wing as an example.
As shown in fig. 2, the grouping of the original structural mesh is given. The automatic grouping process can be seen through a method for searching the boundary condition of the original structural grid, and the automatic grouping can be completed without manual intervention.
As shown in fig. 3, a process of cryptographically reconstructing and then reassembling the lattice blocks of each packet according to the cryptographic coefficients is given. According to the encryption coefficient, the grid blocks of each group are encrypted and reconstructed to obtain a new object plane boundary group, a new far field boundary group and a new middle area group on the left side of the graph 2, the new object plane boundary group, the new far field boundary group and the new middle area group are assembled to obtain an encrypted reconstruction grid, and then boundary conditions of the encrypted reconstruction grid are obtained by updating the boundary conditions among different groups.
As shown in fig. 4, the local details between the encrypted reconstruction grid obtained by the present invention and its different groups are given, the upper right shows the details of the junction of the new object plane boundary group and the new middle area group, and the lower right shows the details of the junction of the new far field boundary group and the new middle area group. It can be seen that the continuous butting boundaries of the grid lines of the original structural grid have been reconstructed into discontinuous splicing boundaries of the grid lines. At this time, the user can use the traditional CFD splicing grid method to perform numerical simulation on the encryption reconstruction grid.
According to the automatic block encryption method for the structural grid, the grid blocks are grouped, the grid encryption reconstruction and the output are completely free of manual intervention, all processes can be automatically operated, the efficiency is high, the stability is high, and errors possibly introduced by manual operation are avoided. Meanwhile, the method is also suitable for some calculation states which need local encryption due to irregular shapes, such as vortex generators and other small-scale components, wing tip vortexes, edge vortex and other complex flow field phenomena, and users only need to specify the grid blocks which need to be encrypted. Meanwhile, the method has no limitation on the specific grid form, so that the method can be generally applied to all forms of the structural grid (butt-joint grid, splicing grid and overlapping grid), thereby having wider application range.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (5)
1. An automatic block encryption method for a structural grid is characterized by comprising the following steps:
firstly, grouping grid blocks of an original structural grid according to boundary conditions of the original structural grid;
secondly, according to the encryption coefficient, on the premise of not changing the space topology of the original structural grid, carrying out encryption reconstruction on each grouped grid block;
step three, the groups after the encryption reconstruction are reassembled, and an encryption reconstruction grid is obtained by updating boundary conditions among different groups;
step four, carrying out various checks on the encryption reconstruction grid, and outputting the encryption reconstruction grid and boundary conditions thereof;
grouping of the original structural mesh, comprising: an object plane boundary group, a far field boundary group and an intermediate zone group;
automatically grouping by adopting a method for searching boundary conditions of the original structural grid:
the grid blocks containing the wall surface boundary are coded into an object surface boundary group;
encoding the grid blocks containing the far-field boundaries into a far-field boundary group;
and encoding the grid blocks of the original structural grid except the object plane boundary group and the far field boundary group into the middle area group.
2. The method for automatically blocking and encrypting the structural grid according to claim 1, wherein the step one of grouping the grid blocks of the original structural grid according to the boundary condition of the original structural grid comprises:
step 1.1, reading the space point coordinates and boundary conditions of the original structural grid;
and step 1.2, automatically grouping the grid blocks of the original structural grid from inside to outside according to boundary conditions of the grid blocks.
3. The method for automatically blocking and encrypting the structural grid according to claim 1, wherein the method for encrypting and reconstructing the grid blocks of each group without changing the spatial topology of the original structural grid according to the encryption coefficient in the second step is:
step 2.1, according to the encryption coefficient, adopting a structural grid reconstruction method to encrypt and redistribute the ridge lines of each grouped grid block on the premise of not changing the space topology of the original structural grid;
step 2.2, according to the encryption coefficient, 6 surfaces of each grouped grid block are encrypted and redistributed, and the 6 surfaces of the grid blocks are projected according to the requirement;
and 2.3, reconstructing the grid blocks of each group by adopting an overrun interpolation method.
4. The structural grid automatic block encryption method of claim 1, wherein the encryption coefficient of each grouped grid block is given by a user according to a specific calculation state.
5. The method for automatic block encryption of structural grids according to claim 1, wherein the method for reassembling the packets after encryption reconstruction and obtaining the encryption reconstruction grid by updating the boundary conditions between different packets in step three comprises:
step 3.1, sequentially refreshing three direction indexes of the grid blocks of each group according to the encryption coefficients;
and 3.2, judging whether the butted grid block of the grid block belongs to the same group with the grid block according to the grid butting relation contained in the boundary condition of the grid block, if the butted grid block belongs to the same group, continuously keeping the butted grid block as the butted boundary, if the butted grid block does not belong to the same group, replacing the butted boundary of the grid block and the butted grid block with a spliced boundary, and giving a new spliced boundary condition.
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