Large eddy simulation of the turbulent flow over a bump

Large eddy simulation (LES) has been applied to prediction of the turbulent boundary layer over a bump. The bump is formed by a prolonged convex surface with two additional short concave surfaces fore and aft; the chordto-height ratio is 15.2:1. A canonical flat plate turbulent boundary layer at a momentum thickness Reynolds number 1,500 is introduced five bump heights upstream of the onset of curvature. The boundary layer is then subject to three changes in sign of streamwise pressure gradient and four changes in sign of surface curvature. The filtered incompressible Navier-Stokes equations are solved using the fractional step method; subgrid scale (SGS) stresses are parameterized using the dynamic eddy viscosity model of Germano et al. (1991). LES predictions of mean velocity and turbulence intensities are in good agreement with the experimental measurements of Webster et al. (1996), though the computed Reynolds shear stress is consistently higher than the measured values.