Three-dimensional numerical simulations and proper orthogonal decomposition analysis of flow over different bottom-mounted ribs

Abstract

Turbulent flow over bottom-mounted ribs is investigated using three-dimensional (3D) Spalart-Allmaras Delayed Detached-Eddy Simulations (SADDES). The ribs are subjected to a boundary layer flow with a thickness of δ/H=0.73 at Re=1∗106(Re=U∞H/ν), where U∞ is the free stream velocity, H is the rib height and ν is the fluid kinematic viscosity. Mesh and time step convergence studies are conducted to determine the grid and time step resolution. The numerical model is validated against the previous published experimental data and numerical results. The effects of different ribs geometries on drag and lift coefficients, the wake flow structures, and the dominant frequencies are discussed. Dominant flow features are investigated by carrying out Proper Orthogonal Decomposition (POD) and quadrant analysis of velocities and pressure in the wake flow.