Large-eddy simulation of flow around a 6:1 prolate spheroid.*

The flow around a 6:1 prolate spheroid at angle of attack is characterized by a range of pressure gradients from favorable on the windward side to adverse on the leeward side, crossflow on the side, and open and close separation of the windward side. Experimental campaigns often trip the flow in order to ensure uniform transition and repeatability of the measurement; however, designing a trip that effectively triggers transition on both sides of the spheroid without over-tripping is challenging due to the range of pressure-gradient. In this context, the wall-resolved, trip-resolved flow around the spheroid at 20^o angle of attack and Reynolds number of 4.2 million is studied using large-eddy simulation. The trip consists of cylindrical posts uniformly distributed azimuthally and placed close to the nose of the spheroid. The sensitivity of the flow to location, geometry and azimuthal distribution of the trip will be evaluated. The results will be compared to the existing experimental data.