Complex water area grid regeneration method based on boundary sewing and expansion

Abstract

The invention provides a complex water area grid regeneration method based on boundary sewing and expansion, which comprises the following steps of step 1, extracting the boundaries of the existing grids, analyzing the existing grids, judging which point is a boundary node, and then extracting the boundaries of the existing grids required to be sewed or expanded; step 2, carrying out the boundarysewing or boundary expansion, when the distance between the boundaries of the two existing grids needing to be connected is relatively shorter, for example, the distance S is smaller than 1.5 D, directly sewing the boundary points of the two grids through triangles or quadrangles; when the boundaries of the two existing grids needing to be connected are farer, for example, the distance S is largerthan 1.5 D, or only one existing grid needs to be expanded, adding the connecting lines, and after a closed area is formed, expanding the grids; and step 3, carrying out the grid regeneration, aimingat a new triangular grid generated by sewing the existing grids and the boundaries or expanding the boundaries, numbering again according to the unstructured grid codes, so that the integral unstructured grid can be obtained, the existing grids can be fully utilized, and the workload of the grid regeneration is greatly reduced.

Description

technical field [0001] The invention relates to the field of simulation of water coefficient values ​​of rivers, in particular to a grid regeneration method for complex water areas based on boundary stitching and expansion. Background technique [0002] So far, almost all numerical simulations of river hydrodynamics are based on grid division. Mesh division accounts for most of the workload of the entire numerical simulation, and the quality of the grid has a certain impact on the calculation accuracy, and the number of grids has a greater impact on the calculation speed, so the division of the grid is particularly important in the numerical simulation. Although the meshing technology is becoming more and more mature, there are still the following problems and shortcomings: [0003] (1) The workload of grid division is heavy, and the existing grids are not fully utilized. According to incomplete statistics, in the numerical simulation calculation of river hydrodynamics, th...

AI Technical Summary

Problems solved by technology

At the same time, sometimes after the grid is completed, due to research needs, the calculation range of the river section needs to be extended, and the grid often needs to be re-divided. The existing grid has not been fully utilized, and the workload of grid division has been increased virtually.

[0004](2) There are many types of grids, and the compatibility of different grids to the model is poor

[0005](3) It is difficult for the same set of grids to meet the needs of both macro and micro calculations

[0006](4) Sometimes it is difficult to meet the grid quantity and quality at the same time

[0007] From the perspective of relatively mature mesh generation software abroad, the Mesh Generator module used in Mike software can easily generate triangular and quadrilateral mixed meshes. The disadvantages are Grid quality is difficult to control effectively; Delft3D software uses RGFGRID module to generate orthogonal curve grids. The disadvantage is that it is difficult to divide complex boundary grids, such as multiple branches, sharp changes in width, etc., and it is difficult to guarantee grid quality; The grid division tool of EFDC software is GEFDC, and RGFGRID software can also be used to generate orthogonal curve grids. Triangular units are merged into quadrilateral units. The disadvantage is that after the grid is generated, some inferior units need to be processed

It can be seen that foreign grid generators can easily generate structured or unstructured grids, but they do not yet have the functions of expanding and stitching existing grids, and also lack the function of splicing structured and unstructured grids, and the grid Poor compatibility of different models

Images