Mitigation of Aero-Optic Distortions by Active Flow Control

Technology in Blscksburg (Techsburg( and the Physics Department at Virginia Tech propose to investigate the potential of both active and passive devices to mitigate the aero-optical distortions generated in a supersonic flow over acylindrical-base/hemi-spherical-top directed energy system turret. A combined suction and blowing system will be used for active flow control, with vortex generators as passive flow control devices. Phase-front distortions of a large diameter laser beamwill be measured using a variable-shear-interferometry techinque.Techsburg has developed a novel method to produce suction and blowing from the same small fluidic actuator that reduces complexity over separate systems and produces more momentum for flow control than traditional blowing. The proposed technique begins byremoving the horse-shoe vortex/boundary layer forming on the wall near the nose of the turret with suction. Next the fluid removed from the nose region and some aditional air will be injected in predetermined directions into the wake of the turret toenhance mixing. The air suction will be generated by the blowing action with the use of the ejector pump technique. Vortex genertors with sized much smaller than the local boundary layer thickness will be placed on the hemi-spherical dome to cratevortices to delay the separation location over the aft section of the turret.