Computations of the BeVERLI Hill Three-dimensional Separating Flow Model Validation Cases

Abstract

The BeVERLI (Benchmark Validation Experiment for RANS/LES Investigations) Hill project aims at producing a detailed experimental database of three-dimensional non-equi- librium turbulent boundary layers with various levels of separation while meeting the most exacting requirements of computational fluid dynamics validation as per Oberkampf and Smith [1]. A group of the Science and Technology Organization (STO) of the North Atlantic Treaty Organization (NATO) entitled NATO AVT-349 - "Non-Equilibrium Turbulent Boundary Layers in High Reynolds Number Flow at Incompressible Conditions" has recently considered the BeVERLI Hill case. Their goal is to advance the accuracy and range of prediction models for high Reynolds number non-equilibrium boundary layers. This highly collaborative and international group comprised of various academic, governmental, and industrial institutions has performed several Reynolds-averaged Navier-Stokes (RANS) simulations of the BeVERLI Hill using different grids, solvers, and turbulence models. The resulting solutions and available experimental data are presented in this paper to summarize and highlight key features, sensitivities, and the current predictive capability of RANS for the BeVERLI Hill case. The results suggest important sensitivities to Reynolds number, grid density, iterative converge, solver, and turbulence models. The RANS predictions are seen to be consistent for the fully attached flow on the windward portion of the BeVERLI Hill. Complex non-equilibrium flow physics pertinent to the BeVERLI Hill case, such as rapid changes in the sign of the pressure gradient over the hill top, three-dimensional curvature, and flow separation on the leeward side of the hill lead to notable scatter in the CFD results and discrepancies relative to the experiment.