Relaxation parameters for the IQE iterative procedure for solving semi-implicit Navier-Stokes difference equations
Numerical solutions of the time-dependent Navier-Stokes equations for a thermally expandable fluid require advancing the unknown flow variables in time by either an implicit, a semi-implicit, or an explicit procedure. Explicit methods require a modest amount of computational effort per time step but require excessively small timestep lengths to ensure numerical stability. On the other hand, implicit and semi-implicit schemes allow the use of large timestep lengths but suffer from increased computational complexities. Fully-implicit methods generate coupled systems of nonlinear equations that must be solved at each point in time, whereas semi-implicit procedures generate coupled systems of linear equations. The focus of this paper is on the use of a recently formulated iterative procedure, called the IQE method, for solving the linear systems produced by a semi-implicit method. The IQE method, for solving the linear systems produced by a semi-implicit method. The IQE method requires the use of a relaxation parameter ..omega.. which must be properly chosen to obtain the greatest rate of convergence. Using heuristic arguments, we develop a numerical procedure for estimating near-optimal values of ..omega... Numerical test results are included.
- Research Organization:
- Bettis Atomic Power Lab., West Mifflin, PA (USA)
- DOE Contract Number:
- AC11-76PN00014
- OSTI ID:
- 5232999
- Report Number(s):
- WAPD-T-2867; CONF-8510149-1; ON: DE85017632
- Country of Publication:
- United States
- Language:
- English
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