Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
Performance of Finite Volume Discretization Schemes in the Backward-Facing Step Problem - Part I: Stability of Schemes
Submission Author:
Gustavo Silva Rodrigues , MG , Brazil
Co-Authors:
Gustavo Silva Rodrigues, Adyllyson Nascimento, José Ricardo Figueiredo
Presenter: Gustavo Silva Rodrigues
doi://10.26678/ABCM.COBEM2019.COB2019-0323
Abstract
The objective of this paper is to evaluate the numerical performance related to the stability of six finite-volume discretization schemes, in the classic benchmarking problem of the two-dimensional backward-facing incompressible step flow. The central differencing (CDS), simple exponential (EXP), first order upwind (FOU), second order upwind (SOU), QUICK and UNIFAES schemes were employed in the discretization of the advective terms of the Navier-Stokes equations in primitive variables using the semi-staggered mesh. The momentum equations are integrated explicitly after the solution of a Poisson pressure equation that ensures mass conservation. The reattachment lengths, as well as the velocity profiles, were obtained as functions of Reynolds number in eight levels of mesh refinement adopted. For low Reynolds numbers all discretization schemes in intermediary or refined meshes produce very similar results. In the case of flows with high Reynolds numbers, EXP scheme and FOU proved to be excessively diffusive, providing unphysical results. The CDS, FOU, and QUICK schemes fail for most of the intermediate meshes, obtaining results only in the most refined mesh for moderate Reynolds numbers. The stability of the SOU and UNIFAES schemes is similar, these two are convergent for any Reynolds number and present better results than the other schemes.
Keywords
backward-facing step flow, laminar flow, Discretization Schemes, Finite Volumes, CFD
