Velocimetry experiments have been performed on a hemisphere-cylinder at Reynolds
number 1000 and angle of attack 20°. At these flow conditions, a pair of vortices, so-called
“horn” vortices, are found to be associated with flow separation. In order to understand the
highly complex phenomena associated with this fully three-dimensional massively
separated flow, different structural analysis techniques have been employed: Proper …
Three-dimensional direct numerical simulations (DNS) have been performed on a finite-size
hemisphere-cylinder model at angle of attack AoA= 20° and Reynolds numbers Re= 350
and 1000. Under these conditions, massive separation exists on the nose and lee-side of
the cylinder, and at both Reynolds numbers the flow is found to be unsteady. Proper
orthogonal decomposition (POD) and dynamic mode decomposition (DMD) are employed in
order to study the primary instability that triggers unsteadiness at Re= 350. The dominant …