Automatic boundary layer calculation-orientated two-dimensional hybrid grid generating method

Abstract

The invention discloses an automatic boundary layer calculation-orientated two-dimensional hybrid grid generating method, which comprises the following steps: embedding an input closed curve into triangular meshes by means of a restriction Delaunary triangularization method to obtain topological approximation edges approximating these curves and triangular meshes inside the curves, outwards propelling a topological approximation edge set as a boundary curve, automatically capturing a topological structure of the propelled new boundary and filling a quadrangular mesh of a propelling region to finally obtain a quadrangular / triangular hybrid mesh meeting the condition and the quality requirement. The automatic boundary layer calculation-orientated two-dimensional hybrid grid generating method is simple and easy to realize, good in reliability, and capable of automatically treating the boundary topological change and collision problem in an propelling process, has no special requirement for an initial two-dimensional closed curve, adapts to the requirement of dense computational grids required by large velocity gradient change in a flow field around a boundary layer, can generate an unstructured triangular mesh with flexible scale change in a place far away from the boundary layer, and can provide the high-quality mesh for correlation calculation of computational fluid mechanics.

Description

technical field [0001] The present invention relates to the fields of computational geometry and computational fluid dynamics, etc. Its purpose is to design an automatic two-dimensional closed curve suitable for arbitrary shapes according to the geometric characteristics of the boundary layer and its surrounding flow field and the needs of computational fluid dynamics. The hybrid grid generation method is applied to the computational fluid dynamics calculation of the boundary layer, so as to improve the accuracy and efficiency of the flow field calculation. Specifically, it involves the discretization of curves, limited mesh division and topology automatic capture of curve boundaries. Background technique [0002] Boundary layer refers to a layer of fluid attached to the solid surface when water, air or other low-viscosity fluid flows along the solid surface or the solid moves in the fluid under the condition of high Reynolds number. Affected by the viscous effect, at the p...

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Problems solved by technology

This method has many advantages, but when dealing with advancing boundary capture, it is found that because it requires higher-dimensional calculations, the solution process is complex and the amount of calculation is large. At the same time, due to numerical dissipation and numerical errors, the obtained triangular elements The quality is unstable, and the method is topology-independent, and there is no connection between the boundaries before and after the advance, so the process of quadrilateral meshing between the advance boundary layers will be more complicated

[0008] To sum up, there are many hybrid grid generation methods based on boundary layer calculations, but there are often problems such as cumbersome calculations, narrow application range, and poor automation. Therefore, the existing algorithms cannot be applied to boundary layer calculations. The hybrid mesh is automatically generated for

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