Active Forebody Vortex Control Using Retractable Miniature Nose-Tip Devices

A pointed slender body at high angle of attack will generate two symmetric vortices resulting from the separation of flow on the leeward side of the body. At critical angles of attack, the vortex shedding becomes asymmetric due to micro-imperfections present at the nose of the body. This asymmetric vortex shedding can result inside forces that may exceed the control capability of the vehicle, and this may cause the body to tumble out of control. The research effort will investigate the effectiveness of introducing retractable miniature flow devices at the nose of a tangent ogive forebody to fix separation points and force the vortex shedding to become symmetric, thus alleviating excessive side forces. Micro-/mini-strakes and miniature perturbations caused by flush-mounted piezo-electric film will be tested to determine their ability to induce symmetric vortex shedding at critical angle-of-attack regimes. The miniature nose attachments will be designed to be deployed/activated by a feedback control system that will monitor side forces due to symmetric vortex shedding. Experimental investigations will be conducted to examine the effectiveness of the concepts.