Large Eddy Simulations of the Flow Around a Square Prism

The aim of this study is to examine unsteady wake flows by means of large eddy simulation (LES). In particular, the flow around a square prism in a channel at a prism-height Reynolds number of 2.14 x 10 4 is studied using different subgrid scale (SGS) models and different grids. Results from first- and second-order statistical moments of the velocity are validated against two sets of experimental data and compared with different Reynolds-average simulations. All LES models correctly reproduce the first- and second-order statistical moments of the resolvable velocity, the global parameters, such as the lift and drag coefficients and their fluctuations, and the Strouhal number, as well as the length of the recirculation region. However, a locally refined grid is necessary to reproduce the maximum velocity within the recirculation region. LES appears virtually independent of the details of the SGS model if it can correctly channel kinetic energy out of eddies close to the cutoff wave number to prevent aliasing provided that the resolution is fine enough to ensure that the cutoff wave number is within the inertial subrange. In addition, phase-averaged flow quantities are compared with experimental data