Numerical investigation of flow past a prolate spheroid

The flow field around a 6:1 prolate spheroid at angle of attack is predicted using solutions of the Reynolds-averaged Navier-Stokes equations and Detached-Eddy Simulation. The calculations were performed for the same conditions as measured by Chesnakas and Simpson¹ and Wetzel et al.¹⁹ The Reynolds number is 4.2 × 10⁶, the flow is tripped at x/L = 0.2, and the angle of attack α is varied from 10 to 20 degrees. RANS calculations are performed using the Spalart-Allmaras one-equation model10 (referred to as 'S-A' throughout). The influence of corrections to the S-A model accounting for streamline curvature and a non-linear constitutive relation are also considered. DES predictions are evaluated against the experimental measurements, RANS results, as well as calculationsperformed without an explicit turbulence model. In general, flow field predictions of the mean properties from the RANS and DES are similar. While initiated further along the spheroid compared to experimental measurements, predictions of primary and secondary separation agree reasonably well with measured values. Solutions of the flow obtained without any explicit turbulence model produce substantial errors in skin friction and pressure distributions.