Nose-tip surface heat reduction mechanism

Hypersonic flow over the nose of a blunt body with a forward-facing cavity is examined. Strong resonant pressure oscillations within the cavity are a common experimental flow feature and occur numerically if either significant freestream oscillations are present or a sufficiently deep cavity is employed. Substantial surface nose-tip cooling is achieved by creating strong longitudinal pressure oscillations within the cavity to induce large bow shock oscillations. Because of the motion of the bow shock relative to the body, the mean stagnation temperature of the airflow into the cavity is reduced. The cooling benefit increases with mean bow shock oscillation speed. Rounding the cavity lip is also necessary to reduce local surface heating since the airflow into the cavity directly impinges on the cavity lip. (Author)