Parametric study of the flow over a 6:1 prolate spheroid*

The prolate spheroid is a canonical geometry that produces a wide range of complex flow phenomena. One of the characteristic features of the flow is the three-dimensional boundary layer separation leading to the formation of one to several coherent counter-rotating vortex pairs in the lee of the body. The behavior of these features are investigated by performing high resolution wall-resolved Large-Eddy Simulations across a large range of incidences between 10 and 90 degrees, and six Reynolds numbers between 0.15M and 4M based on length and free-stream velocity. Results show distinct flow regimes on the spheroid surface as well as a distinct number of vortex state transitions that influence the loads on the spheroid. The nature and origin of these state transitions have important ramifications not only for the flow over the prolate spheroid but also for general blunt body separation at high angle of attack, and will be discussed.