Handling complex boundaries on a Cartesian grid using surface singularities
2001 (English)In: International Journal for Numerical Methods in Fluids, ISSN 0271-2091, E-ISSN 1097-0363, Vol. 35, no 2, 125-150 p.Article in journal (Refereed) Published
This paper considers flow around arbitrarily shaped objects. The boundary conditions on the solid boundaries have been applied by replacing the boundary with a surface force distribution on the surface, such that the required boundary conditions are satisfied. The velocity on the boundary is determined by interpolation or by local (Gaussian space) average. The source terms are determined iteratively as part of the solution. They are then averaged and are smoothed out to nearby computational grid points. The method has been applied both to test problems as well as to more complex engineering problems, where there are not many real competitive alternatives to the proposed method. Simulations of creeping flow around a sphere were studied in order to evaluate the performance of different, competitive approaches of imposing boundary conditions. Using local averaging first-order accuracy is obtained; this can be improved by using a Lagrangian polynomial instead, although the convergence is then considerably slower. Simulations of flows around spheres in the Reynolds number range 1-1000 have been carried out. Finally, the approach was used to describe the impellers in a turbine agitated mixer. For these cases, the results show overall good agreement with other computational and experimental results.
Place, publisher, year, edition, pages
2001. Vol. 35, no 2, 125-150 p.
Cartesian grid, stirred reactor, virtual boundary method, fictitious domain method, rushton turbine, turbulent-flow, simulations, field
IdentifiersURN: urn:nbn:se:kth:diva-20327ISI: 000166732200001OAI: oai:DiVA.org:kth-20327DiVA: diva2:339022
QC 201005252010-08-102010-08-10Bibliographically approved