MIDIT OFD CATS Modelling, Nonlinear Dynamics Optics and Fluid Dynamics Chaos and Turbulence Studies and Irreversible Thermodynamics Risø National Laboratory Niels Bohr Institute and Technical University of Denmark Building 128 Department of Chemistry Building 321 P.O. Box 49 University of Copenhagen DK-2800 Lyngby DK-4000 Roskilde DK-2100 Copenhagen Ø Denmark Denmark Denmark
by Chuanju XU
Department of Mathematics
Laboratoire J.A. Dieudonne de Mathematiques,
UNSA, 06108 Nice, France
Tuesday June 15, 1999, 14-15 h
at ET, Institute of Energy Engineering
Fluid Mechanics, Building 404, Room 215
Efficient methods are proposed to solve the non-linear incompressible
Navier-Stokes/Euler coupled equations.
Based on a new global variational formulation, the coupled problem gives
rise to a global saddle problem. Classical Uzawa algorithm decouples the
original saddle problem into two positive definite symmetric systems.
It is shown that, provided appropriate preconditioner is chosen for the pressure
system, the nested conjugate gradient methods can be applied to obtain rapid
An iteration-by-subdomain method has also been investigated. The convergences are proven both in the differential case and in their spectral collocation counterpart. Detailed analysis shows that the iterative algorithms converge with a rate independent of the polynomial degree. A validation study is carried out by simulating the flow past a cylinder.