WALL-MODELED LARGE-EDDY SIMULATION OF AXIAL FLOW OVER A SLENDER BODY OF REVOLUTION

The effectiveness of wall-modeled large-eddy simulation in predicting flow over axisymmetric bodies is investigated through the application of an equilibrium wall model to axial flow over the bare-hull DARPA SUBOFF body. Flow is numerically tripped with steady wall-normal blowing in all cases, and simulations are performed at Re = 1.1×10⁶ and Re = 1.2×10⁷. Preliminary simulations of flat plate flow demonstrate the ability of the wall model to reproduce the behavior of the law of the wall. However, when applied to axial flow over the SUBOFF body, the wall model fails to predict axisymmetric law of the wall behavior. The capability of the wall model to successfully predict flows where the pressure gradient is nonzero is demonstrated in simulations of flow over a step with the profile of the SUBOFF body. Simulations of axial flow over cylinders of increasing radii reveal the limitations of the wall model in resolving three-dimensional boundary-layer effects associated with transverse wall curvature when the radius of curvature is comparable to the boundary-layer thickness. A correction based on the formulation of the axisymmetric law of the wall is implemented in the wall model to improve the wall shear stress prediction. The correction brings the wall model result closer to the result as predicted by wall-resolved large-eddy simulation, but the effectiveness of the correction decreases with increasing Reynolds number.