In calculating low Mach number flows one faces the stiffness problem in two different facets: β’ the applicable time steps become very small β’ the constants of the cancellation errors become very large (1/Ξ³ M 2 ). Usually the first point receives attention. Here we want to concentrate on the cancel
Cancellation problem of preconditioning method at low Mach numbers
β Scribed by Sang-Hyeon Lee
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 663 KB
- Volume
- 225
- Category
- Article
- ISSN
- 0021-9991
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β¦ Synopsis
The effects of cancellation errors on the convergence characteristics of preconditioned Navier-Stokes equations at low Mach numbers are analyzed. Laminar viscous flows around a circular cylinder are calculated at different Mach numbers. It is shown that the cancellation error in the energy equation grows faster than those in the other equations, as the Mach number decreases. It is also shown that the cancellation problem of the energy equation is due to the off-diagonal element that is related to a pressure change in the preconditioner.
π SIMILAR VOLUMES
A semi-implicit numerical method for time accurate simulation of compressible flow is presented. By extending the low Mach number pressure correction method, a Helmholtz equation for pressure is obtained in the case of compressible flow. The method avoids the acoustic CFL limitation, allowing a time