Filtering non-solenoidal modes in numerical solutions of incompressible flows

✍ Scribed by William J. Rider

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 775 KB
• Volume: 28
• Category: Article
• ISSN: 0271-2091
• DOI: 10.1002/(sici)1097-0363(19981015)28:5<789::aid-fld728>3.0.co;2-4

✦ Synopsis

Solving the incompressible Navier-Stokes equations requires special care if the velocity field is not discretely divergence-free. Approximate projection methods and many pressure Poisson equation methods fall into this category. The approximate projection operator does not dampen high frequency modes that represent a local decoupling of the velocity field. For robust behavior, filtering is necessary. This is especially true in two instances that were studied: long-term integrations and large density jumps. Projection-based filters and velocity-based filters are derived and discussed. A cell-centered velocity filter, in conjunction with a vertex-projection filter, was found to be the most effective in the widest range of cases.