Instabilities of flows over bodies at large incidence

The phenomena of the flow about an ogive-cylinder placed at incidence to an oncoming stream were numerically investigated for angles of attack of 60 and 80 deg.The flow around the cylindrical part of the body became unsteady, and vortex shedding was observed. For the 80-deg case, the corresponding Strouhal frequency was about 0.2. For both angles of attack, a small temporal disturbance of finite duration was sufficient to trigger the unsteadiness, which evolved to a finite amplitude fluctuation in the wake