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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
NUMERICAL SOLUTION OF THE FLOW CONTROL IN A BACKWARD-FACING STEP FOR VARIOUS REYNOLDS NUMBERS
Submission Author:
Deidson Vilhena Santos , RS , Brazil
Co-Authors:
Deidson Vilhena Santos, Alvaro de Bortoli
Presenter: Deidson Vilhena Santos
doi://10.26678/ABCM.ENCIT2020.CIT20-0406
Abstract
The Backward-Facing Step flows have been widely studied aiming optimization of flows and, most recently, control strategies have been applied for it. So, in this work a numerical investigation of the effect of a closed-loop control for a flow in a backward-facing step, whose expansion ratio is 3.0, is given. The flow equations are the incompressible set of Navier-Stokes equations, while the control equations are given in the state-space formulation. The flow solution is obtained via Computational Fluid Dynamics using the Runge-Kutta method, where the equations are discretized by centered finite differences scheme. The analysis is given for four Reynolds numbers (50, 100, 300 and 500) whose recirculation zone and instabilities increase considerably as Re increases. The results of the flow fields have been validated with data from the literature, through the length of the recirculation zone and the vorticity fields, obtaining good agreement in the comparisons. In the investigation of the effect of the control applied on the flow, it was noted the characterization of an oscillatory profile, obtaining: better and more efficient mixing pattern; anticipation of 12.43% at x-position of the point of reattachment; 18.9% reduction in the length of the recirculation zone; and 753.23% increase in the flow speed at a pre-established point.
Keywords
Backward Facing Step, Navier-Stokes Equations, Closed-loop control, computational fluid dynamics.
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