Large eddy simulation on a square cylinder near a plane boundary

Abstract

Steady flow around the square cylinder with a plane boundary has been investigated through three-dimensional large eddy simulation in the present work. The influence of the gap ratio at high Reynolds number has been summarized by analysing hydrodynamic characteristics around the square cylinder with a plane wall boundary. A three-dimensional numerical mesh is built through structured mesh with multiple meshing strategies. The numerical results have a good agreement with the experimental results at high Reynolds number scenario. The influence of the plane boundary on the pressure distributions and averaged hydrodynamic characteristics has been quantified. The refinement of the meshing in the vicinity and the wake provides a solution to accurate predict the hydrodynamic forces and the flow structures for a near-wall square cylinder. A sharp pressure recovery is found next to the leading edge is ascribed to the flow reattachment at the lower surface. The vortex formation length Lf is found to be increased monotonically with the decrease of the gap ratio, which is ascribed to the extended lower recirculation due to the blockage effect. The maximum wake width W is observed at G/D = 0.5, corresponding to the large base pressure. The interaction of the Kelvin-Helmholtz vortices and von Kármán vortex street has been clearly captured through.