Subsonic to Supersonic Wake Stabilization Using Discrete Porosity

The feasibility of using discrete suction to improve the laser optics environment associated with a hemisphere-and-cylinder turret was investigated using computational fluid dynamics. Simulations were conducted at Mach numbers of 0.5, 0.7, and 1.5. The discrete suction control generates and positions a large-scale counter-rotating vortex pair that induces a strong downwash over the hemispheric beam director. Flow attachment is maintained regardless of the position of the optical window and whether a shock is present. The density fluctuation in the wake is greatly reduced. Consequently, an improvement in the optical environment over the baseline can be expected for the Mach number range studied.