Wall-Resolved Large-Eddy Simulation of Flow over a Three-Dimensional Gaussian Bump

Abstract

Wall-resolved large-eddy simulations were carried out for the flow over a Gaussian bump configuration, that is representative of surfaces generating smooth-body separation. The geometry and flow conditions were motivated by an experimental investigation, which was conducted in order to provide data for validating numerical modeling. Because the high Reynolds number and three-dimensional shape of the experimental model is challenging, even for approximate numerical techniques, the present computations were initiated in order to provide benchmark results that are accessible via wall-resolved large-eddy simu- lation. It was found that by increasing the bump height, the Reynolds number could be reduced and flow separation would occur. The modified bump then serves as a surrogate for the original Gaussian bump producing a smooth separated flow. Solutions to the un- steady three-dimensional compressible Navier-Stokes equations were obtained utilizing a high-fidelity computational scheme and an implicit time-marching approach. Preliminary computations to determined the modified bump height were carried out with a limited span and periodic conditions, so as to minimize computational resources for parametric studies. Once the flow conditions and height of the modified bump were determined, large-eddy simulations were performed for both spanwise-invariant and fully three-dimensional con- figurations. Grid resolution studies were created for both cases, and a number of metrics are provided to attest to the quality of the computed solutions. Numerical flowfields of the respective configurations are compared, and features of the computations are elucidated.