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COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Numerical Simulation of Turbulent Flow Over a Backward-Facing Step
Submission Author:
Filipe Alcântara Soares , RJ
Co-Authors:
Priscila Araujo, André Luiz Tenório Rezende, Filipe Alcântara Soares
Presenter: Filipe Alcântara Soares
doi://10.26678/ABCM.COBEM2017.COB17-0385
Abstract
The flow over a backward-facing step is a complex case in the scope of computational fluid dynamics, present in several engineering examples. In fact, its complexity is due to adverse pressure gradient which affects a separation of the boundary layer, thus presenting separation, recirculation and reattachment of the flow steps. In the present work all these steps are analyzed numerically in a simplified way through the construction of a case with a simple geometry. To numerically simulate this case, were used Reynolds Average Navier-Stokes equations (RANS) for a two-dimensional steady state flow and the turbulence models used are the k-ω and SST k-ω. The expansion ratio is ER=2 and the Reynolds number, based on the step height and mean inlet velocity is Re = 9000. Results were compared with data from the literature using direct numerical simulation (DNS). The results for both simulated models were satisfactory and close to those found in direct numerical simulation. The results presented in the SST k-w model are closer to the results expected and found by the use of direct numerical simulation due to their better application in cases involving adverse pressure gradient and boundary layer separation. The main results analyzed in this paper are reattachment length, mean velocity and pressure coefficient.
Keywords
BFS, RANS, Reattachment, k-w, SST k-w
