Passive Control of Transonic Shock-Wave–Boundary-Layer Interactions over a Blunt Nose Body Using Aerodiscs

The payload fairings of launch vehicles with blunt nose cones are prone to transonic buffet excitation due to high levels of pressure fluctuations caused by shock-wave–boundary-layer interactions (SWBLI) at small angles of attack. The problem becomes crucial when the semi-nose-cone angle exceeds [Formula: see text]. The present work focuses on mitigating SWBLI by energizing the boundary layer growing over the payload region so that it does not respond to shock oscillations, even when the semi-nose-cone angle is [Formula: see text] or [Formula: see text]. The technique involves an aerodisc comparable to an aerospike mounted upstream of the nose cone. The eddies shed by the aerodisc impinge on the nose cone, where the pressure gradient for the boundary layer is highly favorable. Due to the receptivity of the boundary layer, the turbulent kinetic energy associated with the boundary layer is enhanced. Consequently, as the boundary layer grows over the payload region, the shock oscillations are suppressed. Thus, the pressure fluctuations over the [Formula: see text] nose can be controlled to reach the levels reached with a [Formula: see text] nose. It is thereby demonstrated that the aerodisc mounted on bulkier payloads controls SWBLI and modifies the buffet environment over the payload region. Limited parametric studies to optimize the aerodisc geometry are presented.