Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
Incompressible Flows Bifurcation Phenomena in Symmetric Channels
Submission Author:
Gustavo Silva Rodrigues , MG , Brazil
Co-Authors:
Adyllyson Nascimento, Gustavo Silva Rodrigues, José Ricardo Figueiredo
Presenter: Gustavo Silva Rodrigues
doi://10.26678/ABCM.COBEM2019.COB2019-0708
Abstract
This paper presents a numerical study of the incompressible laminar flows bifurcation phenomena in a two-dimensional symmetric sudden expansion. The solution method of the continuity and Navier-Stokes equations for incompressible flows is based on the Eulerian description of the flow. It uses the primitive variables in the divergent form, in the context of the finite volume, with the UNIFAES scheme for the discretization of the spatial derivatives of the advective-diffusive transport equation. The solution method adopts the explicit time integration procedure of the velocity field and uses the Poisson equation for the pressure field. The solution of the Poisson equation is obtained with several iterations per velocity step in order to ensure mass conservation throughout the transient regime. In comparative studies in this context, the almost unknown semi-staggered mesh structure has been highlighted by accuracy, in relation to the traditional staggered and collocated meshes. Like the semi-staggered mesh, the UNIFAES scheme is justly following this path of extensive evaluation, presenting good performance regarding acuity and stability in the most diverse types of problems previously evaluated. The flow in symmetric channels is known to exhibit a stable symmetric solution up to a critical Reynolds number above which symmetry-breaking bifurcation occurs. The present paper has the contribution of presenting new numerical evaluations of the continuity and Navier-Stokes equations, thus extending the scope of the UNIFAES discretization scheme and the semi-staggered mesh, as well as the methodology used to solve the equations. The results of the numerical procedure are compared with experimental and numerical studies available in the literature.
Keywords
Numerical Methods, Sudden Expansion, Finite Volume, UNIFAES, Semi-staggered Mesh
