Turbulent flow over a D-section bluff body: a numerical benchmark

Abstract

A numerical benchmark of different turbulence closures was performed to investigate the turbulent wake flow behind a submerged D-shaped bluff body. The numerical models included steady two-equation Reynolds-Averaged Navier–Stokes models and Large Eddy Simulations (LES), which were compared to planar and stereoscopic particle image velocimetry measurements. The k- $$\omega$$ SST low-Reynolds number model was found to be better adapted to capture the intense shear layer at the top of the D-section compared to the other two-equation models. Yet, the k- $$\epsilon$$ and k- $$\omega$$ SST high-Reynolds number models demonstrate higher performance in the recirculation region. LES was also performed over the D-section to determine the influence of the sub-grid scale models on the prediction of the vortical structures. The Wale model together with central difference schemes showed a better overall agreement over the standard Smagorinsky model, which appears too dissipative. A spectral analysis was performed in the wake region, yet no distinct shedding frequencies could be found. A proper orthogonal decomposition was applied to the LES results to extract the mean flow dynamics and the coherent structures.