Computational fluid dynamics; Low Mach number flows; Unsteady flow preconditioning
Abstract :
[en] This paper presents a density-based finite volumes method for solving the unsteady Navier-Stokes equations on 3D unstructured grids. The second order Crank-Nicolson scheme is applied to perform the time integration. At each time step, the system of non linear equations is solved by means of a fully implicit dual time stepping method.An eigenvalues analysis demonstrates that this system can be ill-conditioned in the case of low Mach number flows for a certain range of CFL numbers. A new unsteady preconditioning technique, taking the CFL number into account, is proposed to improve convergence and accuracy. A second order and first order discretization schemes of the advective and viscous terms respectively are applied. The advective upwinding is performed by the AUSM+up scheme. The latter is modified to achieve robustness and accuracy for all Mach and CFL numbers.
Disciplines :
Mathematics Mechanical engineering
Author, co-author :
Vigneron, Didier ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > LTAS - Aérodynamique
Deliège, Geoffrey ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > LTAS-Aérodynamique
Essers, Jean-André ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > LTAS - Aérodynamique
Language :
English
Title :
Low Mach Number Local Preconditioning For Unsteady Viscous Finite Volumes Simulations on 3D Unstructured Grids
Publication date :
2006
Event name :
European conference on computational fluid dynamics - ECCOMAS CFD 2006
Event place :
Egmond aan Zee, Netherlands
Event date :
September 5-8, 2006
Audience :
International
Main work title :
ECCOMAS CFD 2006: Proceedings of the European Conference on Computational Fluid Dynamics
Editor :
Wesseling, P.
Onate, E.
Périaux, J.
Publisher :
Delft University of Technology, Delft, Netherlands
