Third M.I.T. Conference on Computational Fluid and Solid Mechanics June 14–17, 2005  

Study of unsteady flow past a circular cylinder using a new computational approach at the outflow boundary

Syed Fahad Anwer, Nadeem Hasan, Sanjeev Sanghi*
Department of Applied Mechanics, Indian Institute of Technology, Delhi, New Delhi-110016, India

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This work presents a new procedure for extrapolating velocities at the outflow boundary from the interior in the computations of incompressible flows around rigid bodies. It has been demonstrated via numerical simulations of 2D, laminar, incompressible, viscous flow past a circular cylinder at Re=100 and an impulsively started circular cylinder at Re=550, that the usage of the proposed boundary condition allows one to limit the unbounded domain to a small size (6-8 times the characteristic size of the body) without any significant change in the flow characteristics like the lift coefficient (CL) and the Strouhal number (St). Thus, the proposed boundary conditions can enhance the computational efficiency of this class of flows.

Keywords:  Outflow boundary condition; CFD; SMAC; Cylinder; Uniform flow; Strouhal number; Convective boundary condition; Low Reynolds number; curvilinear coordinate system; Navier-Stokes equation

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