MASK GENERATOR FOR ORTHOGONAL REGULAR MESH

Радіоелектронні і комп'ютерні системи

Vladislav Sereda¹  Maya Ambrozhevich¹ 

[1] National Aerospace University “Kharkov Aviation Institute”, Kharkov;

关键词: computational grid;    volume mask;    surface mask;    cosine mask;   

DOI  :  10.32620/reks.2020.4.04

来源: DOAJ

【 摘 要 】

Existing mesh generators are focused mainly on obtaining non-orthogonal irregular grids designed to describe the curved boundaries of streamlined bodies. However, the thickening of the grid leads to an increase in the calculation time, and the non-conformity of the grid leads to unphysical effects. The software package (SP) developed by the authors for the simulation of gas-thermodynamic processes is oriented toward a much simpler description of the geometry, i. e., uses a different principle of increasing the smoothness of the solution in places with a complex surface structure. This principle consists in superimposing on the flow such sources of momentum and energy, which are equivalent in their effect on the flow to the interaction with the solid wall. SP contains a mask generator of an orthogonal regular grid. The initial data for building the mask is a 3D model created in any CAD application, which is saved in the STL format and placed in the project directory. Each cell contains information about the presence of a three-dimensional solid, the permeability of each face of the hexahedron, and the direction of the normal vector to the streamlined surface. In this regard, the generator creates three types of masks: volumetric, surface full and incomplete permeability, as well as a mask of guiding cosines. To obtain a volume (solid) mask from the center of each cell along the axes, a straight line is drawn and its intersection is checked with each triangle approximating the surface of the body under study. An odd number of intersections of triangles and a straight line indicates the presence of a volume mask in the cells. A surface impermeable mask is formed in three directions at the free cell section and the occupied volume mask. If it is necessary to introduce a semipermeable mask, its localization and measure are assigned by the user. The mask of the guiding cosines is assigned in the cell, which is adjacent to the surface impermeable mask. The values of the guiding cosines are assigned equal to the corresponding values of the nearby triangle approximating the surface of the 3D model. The generated masks are formed as separate files. A SolidWorks application has been developed that allows for volumetric visualization. In the decisive program, the information about the presence of the volume mask is used as follows: the volume mask is excluded from the solution area, self-similar problems are solved near the surface, and if there are guiding properties, an isentropic flow rotation is performed.

【 授权许可】

Unknown