On the use of adaptive hierarchical meshes for numerical simulation of separated flows

✍ Scribed by Deborah M. Greaves; Alistair G. L. Borthwick

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 357 KB
• Volume: 26
• Category: Article
• ISSN: 0271-2091
• DOI: 10.1002/(sici)1097-0363(19980215)26:3<303::aid-fld643>3.0.co;2-y

✦ Synopsis

This paper describes the use of adaptive hierarchical grids to predict incompressible separated ¯ow at low Reynolds number. The grids consist of a quadtree system of hierarchical Cartesian meshes which are generated by recursive subdivision about seeding points. The governing equations are discretized in collocated primitive variable form using ®nite volumes and solved using a pressure correction scheme. The mesh is locally adapted at each time step, with panel division or removal dependent on the vorticity magnitude. The resulting grids have ®ne local resolution and are economical in array size. Results are presented for unidirectional, impulsively started ¯ow past a circular and a square cylinder at various Reynolds numbers up to 5000 and 250 respectively. It is clear that hierarchical meshes may offer gains in ef®ciency when applied to complex ¯ow domains or strongly sheared ¯ows. However, as expected, the stepped approximation to curved boundaries resulting from the Cartesian quadtree representation adversely affects the accuracy of the results for ¯ow past a circular cylinder.