Component-based hybrid mesh generation

Abstract

SUMMARYThis paper presents a method for generating computational meshes by building structured component grids and then connecting them with an unstructured mesh. The approach uses technologies from the overset grid community, specifically the Ogen overlapping grid generator from the Overture framework, to build a collection of overlapping structured grids for a given geometry. Overlapping regions between the component grids are automatically removed and replaced with an unstructured mesh that conforms to the boundaries of the holes in the structured grids. Large regions of high-quality structured grids comprise most of the domain and are connected by a comparatively small amount of unstructured mesh. A method for generating hybrid surface meshes from overlapping and intersecting surface grids is also described. These surface meshes preserve the geometry used to generate the structured grids by querying the original geometry database. An implementation of advancing front mesh generation creates the interstitial surface and volume unstructured meshes. Mesh spacing information is automatically computed from the original overlapping grid. The mesh is optimized by regeneration in areas of poor quality as well as vertex repositioning by non-linear optimization of a quality metric. Quality assessment is accomplished by incorporating the mesh spacing information into algebraic mesh quality metrics. A description of the approach and algorithms is presented followed by two-and three-dimensional demonstrations. Published in 2004 by John Wiley & Sons, Ltd.

Hybrid grid generation for viscous flow analysis

“…The equation of the quadric surface at the local coordinate is represented as Equation (4). Note that there are no x, y and constant terms because the tangent plane of the surface equals xy-plane at the origin.´D between p and its neighbor vertex.…”

“…The pros and cons of each type are well discussed in the literatures such as Baker [2]. For this reason, a hybrid mesh consisting of a body-fitted structured mesh layer and an unstructured background mesh has gained the attention of CFD researchers for viscous flow analysis in recent years [3][4][5][6][7][8][9][10][11][12][13] including its use in several commercially available software programs such as VisCART, Harpoon, and GDT. However, a structured grid makes unnecessarily dense elements in areas far from focal objects to achieve the resolution required in the critical part of the domain.…”

“…It is believed that a structured grid created in body-fitted fashion is superior for capturing viscous flow near the objects' surface because of the orthogonality of elements to the dominant flow direction [3]. Chand [4] proposed a structured-unstructured hybrid mesh for overlapping multi-body 892 S. PARK ET AL. Moreover, it is not a simple task to automatically create a body-fitted structured mesh for objects with complex geometry.…”

“…Our mesh has smaller number of cells than the approaches using body-fitted cells and tetrahedrons [4,6,10] because of an adaptive Cartesian mesh. Unlike several other approaches such as [5], which stop stacking body-fitted cells and fill with unstructured cells in that region, the bodyfitted layer avoids local interferences and global interferences in a systematic way by using level set approach without losing parametric information of the surface boundary.…”

Conforming Hybrid Mesh Generation for Solids with Tubular Holes

“…The hybrid mesh has the high mesh quality strategy and contains fewer elements than all-tetrahedral mesh. A number of hybrid mesh generation methods have been developed and implemented for complex geometries [2,9,11].…”