Title: Simulation of vortex dynamics in a cylinder wake by the Immersed Boundary technique

Authors: Sudipto Sarkar, S. Sarkar

Addresses: Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India. ' Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India

Abstract: The dynamics of flow past a circular cylinder is investigated at Reynolds number (Re) between 20 and 3900 using the rectangular mesh. The Re is defined based on the cylinder diameter D and the free-stream velocity U_∞. This is achieved by using the Immersed Boundary (IB) method that helps to impose boundary conditions on a given surface not coinciding with the computational grid. Two interpolation techniques, namely bi-linear proposed by the authors and unidirectional quadratic by Muldoon and Acharya (2005), are compared for both the laminar and the turbulent flow regime. The unsteady Navier–Stokes (N–S) equations are solved using a symmetry-preserving finite-difference scheme of second-order spatial and temporal accuracy. Large-Eddy Simulations (LES) with the dynamic subgrid model are used to resolve the turbulent flow at Re = 1000 and 3900. When compared with experiments, it reveals that the IB method is worth pursuing and both the interpolations generate almost identical results for a wide range of Reynolds numbers. The bi-linear interpolation is easy to implement and take less computational time because of its simplicity.

Keywords: immersed boundary method; LES; large-eddy simulations; circular cylinders; vortex dynamics; cylinder wake; laminar flow; turbulent flow.

DOI: 10.1504/PCFD.2010.033325

Progress in Computational Fluid Dynamics, An International Journal, 2010 Vol.10 No.3, pp.129 - 145

Published online: 25 May 2010 *

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