A virtual boundary method with improved computational efficiency using a multi-grid method

Research output: Contribution to journalArticle


The flow around spherical, solid objects is considered. 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 extrapolation from the flow field. The source terms are determined iteratively, as part of the solution. They are then averaged and are smoothed out to nearby computational grid points. A multi-grid scheme has been used to enhance the computational efficiency of the solution of the force equations. The method has been evaluated for flow around both moving and stationary spherical objects at very low and intermediate Reynolds numbers. The results shows a second order accuracy of the method both at creeping flow and at Re = 100. The multi-grid scheme is shown to enhance the convergence rate up to a factor 10 as compared to single grid approach. Copyright (C) 2004 John Wiley Sons, Ltd.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Fluid Mechanics and Acoustics


  • boundaries, sphere, multi-grid, virtual boundary method, Cartesian grid, moving
Original languageEnglish
Pages (from-to)775-795
JournalInternational Journal for Numerical Methods in Fluids
Issue number7
Publication statusPublished - 2004
Publication categoryResearch