LES of turbulent flow past a swept fence

The present study deals with the large-eddy simulation of the span-wise invariant turbulent flow past a swept fence at low Reynolds numbers. The swept fence geometry was introduced by McCluskey et al. [Eighth Symposium on Turbulent Shear Flows, 1991, p. 9.5.1] as a way of gathering information on the behaviour of near wall flows beneath a separation region in the presence of a significant cross flow. The configuration avoids both the lack of generality of typical statistically two-dimensional flows and the difficulties of fully three-dimensional flows. In the present case, large-eddy simulation is both a challenging and promising approach. On the one hand, as in most low-Reynolds number and recirculating flows, simple wall models cannot be applied [Engineering Turbulence Modelling and Experiments 2, Florence, Italy, p. 3031 on the other hand, due to the relatively low Reynolds of the flow and the type of scaling suggested in Hardman and Hancock [Exp. Fluids 27 (2000) 6531, accurate resolution of the near wall region can be achieved without incurring prohibitively high computational costs. A variant of the dynamic SGS model of Germano et al. [Phys. Fluids A 3 (1991) 1760] with a smooth and reliable numerical behaviour is also tested in this flow. The agreement with the experimental data of Hardman [Moderately three-dimensional separated and reattaching turbulent flow. Ph.D. thesis, University of Surrey, 1998] is found to be satisfactory. (C) 2003 Elsevier Science Inc. All rights reserved.