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CivilComp Proceedings
ISSN 17593433 CCP: 94
PROCEEDINGS OF THE SEVENTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: B.H.V. Topping, J.M. Adam, F.J. Pallarés, R. Bru and M.L. Romero
Paper 58
Automatic Generation of Hexahedral Meshes for Volumes with NonPlanar Surfaces using the MultiSweeping Method E. RuizGironés, X. Roca and J. Sarrate
LaCàN, Department of Applied Mathematics III, Universitat Politècnica de Catalunya, Barcelona, Spain E. RuizGironés, X. Roca, J. Sarrate, "Automatic Generation of Hexahedral Meshes for Volumes with NonPlanar Surfaces using the MultiSweeping Method", in B.H.V. Topping, J.M. Adam, F.J. Pallarés, R. Bru, M.L. Romero, (Editors), "Proceedings of the Seventh International Conference on Engineering Computational Technology", CivilComp Press, Stirlingshire, UK, Paper 58, 2010. doi:10.4203/ccp.94.58
Keywords: mesh generation, hexahedral mesh, multisweeping, computational domain, geometry decomposition.
Summary
The generation of unstructured hexahedral meshes is still an open
problem. Several methods have appeared in the literature to generate
such meshes. However, an unstructured hexahedral mesher that can
discretize any arbitrary geometry does not exist. Therefore, specific
algorithms have been developed for specific types of geometries that
often appear in industrial applications. For instance, sweep
algorithms [1,2,3,4]
have been successfully applied for extrusion geometries defined by a
single source surface and a single target surface (onetoone
sweeping algorithms). This method evolved into the manytoone
algorithm [5] that allows meshing extrusion volumes with
several source surfaces but a single target surface. The method
decomposes the initial geometry into onetoone barrels that can be
meshed using a onetoone sweeping scheme. In the last years, several
algorithms have appeared to mesh manytomany extrusion volumes
(multisweeping algorithms) [6,7]. This
algorithm decomposes the volume into manytoone subvolumes. Then,
each subvolume is further decomposed into onetoone barrels. The
decomposition is performed by means of projecting nodes along the
sweep direction and imprinting surfaces.
However, the quality of the final mesh is directly related to the robustness of the imprinting process and to the location of inner nodes created during the decomposition process, especially for geometries with curved surfaces. To overcome these drawbacks, we propose two original contributions. On the one hand, we introduce the new concept of the computational domain for sweep geometries. The computational domain is a planar representation of the sweep levels and it permits improvement of several geometric calculations performed during the imprinting process. This results in a more robust imprinting process. On the other hand, we propose to improve the location of inner nodes by performing a threestage decomposition process. In the first stage, we project the nodes on target surfaces to source surfaces. At this stage, the decomposition of the geometry is determined, but it is desirable to improve the location of inner nodes. To this end, in the second stage, we project back the nodes from source surfaces to target surfaces. In the third stage, the final location of inner nodes is computed as a weighted average of the nodes projected from target surfaces and the nodes projected from source surfaces. References
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