Tripping effects on the flow around a 6:1 prolate spheroid using large-eddy simulation*

The flow around an inclined 6:1 prolate spheroid is a commonly studied canonical problem that exhibits a variety of complex phenomena found in immersed bodies at angle of attack.  These features include three-dimensional boundary layers, smooth separation and several mechanisms of natural transition including Tollmien-Schlichting, centrifugal and crossflow instabilities. The boundary layer of the prolate spheroid is often tripped in experiments and numerical studies to ensure reproducibility and high Reynolds number behavior. The present study aims at understanding the effects of tripping on the prolate spheroid flow using large-eddy simulation. A wall-resolved and trip-resolved approach is taken to investigate the performance of the trip at 20^o angle of attack and at a Reynolds number of 4.2 million based on length and freestream velocity. An overset methodology is used to model the trip setup used in the reference experiment, which consisted of a set of cylindrical posts at 20% of the length. Comparison to experiment and analysis of the results will be presented.