Flow over two tandem wall-mounted cubes using large eddy simulation

Abstract

Flow over tandem surface-mounted cubes in a channel were investigated numerically using large eddy simulation (LES). The selective structure function model used for the determination of eddy viscosity appears in the subgrid scale stress terms in momentum equations. Flow over this geometry has very complex phenomena such as several horseshoe vortices and recirculation regions. The main objective of this study is identifying the features of flow past two in-line wall-mounted cubes in a channel for Reynolds number 22 000. The LES results obtained are in reasonable agreement with the experiment both qualitatively and quantitatively. The time-averaged streamlines and velocity vectors were compared with the experiment of Martinuzzi and Havel [9], which showed good correspondence. The S/H length has negligible influence on the turbulence levels in the region upstream and above the first cube in the separation zone. However, in the vortex core downstream of, and above the second cube, elevated levels of turbulence were found for both u′u′ and v′v′ especially when the inter-obstacle spacing is increased. A result of this study also includes time-averaged contours of turbulent intensity and some details of flow parameters such as the Strouhal number and drag coefficient.