Computation of the Flow Over a Sphere at Re = 3700: A Comparison of Uniform and Turbulent Inflow Conditions

Abstract

A highly resolved computation of the flow past a sphere at Reynolds number Re = 3700 using a finite element method (FEM)-based residual-based variational multiscale (RBVMS) formulation is performed. Both uniform and turbulent inflow conditions are considered with the uniform flow case validated against a previous direct numerical simulation (DNS) study. We find that, as a result of adding free-stream turbulence of moderate intensity, the drag force on the sphere is increased, the length of the recirculation bubble is reduced dramatically, and the near-wake turbulence is significantly more energetic than in case of uniform inflow. In the case of uniform inflow, we find that the solution exhibits low temporal frequency modes, which necessitate long-time simulations to obtain high-fidelity statistical averages. Subjecting the sphere to turbulent inflow removes the low-frequency modes from the solution and enables shorter-time simulations to achieve converged flow statistics.