Visualization and measurement of shock movement during transonic limit-cycle oscillation

Abstract

For more than 30 years, the phenomenon of shock-induced, trailing-edge separation has been investigated experimentally and numerically to determine whether it alone can produce a sufficiently large nonlinear force such that limit-cycle oscillation occurs in transonic flight. However, none of those research efforts have observed, much less measured the shock movement associated with shock-induced, trailing-edge separation in flight. The investigation described herein was able to both observe and measure shock movement during transonic limit-cycle oscillation in flight. The results provide conclusive evidence of the correlation between the observed shock movement and the limit-cycle oscillations, and suggest the presence of a nonlinear aerodynamic force.