LINEAR STABILITY OF THREE-DIMENSIONAL COMPRESSIBLE SWEPT-WING BOUNDARY LAYER

Stability of three-dimensional swept-wing boundary layers has been investigated in the framework of the linear theory. The analysis is based on the assumption of local self-similarity of the basic flow and was performed within Falkner-Scan-Cook solution generalized for compressible flows. It has been established that computed subsonic swept-wing boundary-layer stability characteristics correlate well with the experiment. For the supersonic Mach=2 boundary layer computations agree with measurements for spanwise scales of the unstable cross-flow disturbances. However theoretical growth rates differ considerably from measured. This distinction is explained by high intensity of the initial perturbations excited in the experiment that does not allow to apply linear theory. Development of the natural disturbances is described by the theory good enough. It is shown that influence of the compressibility on cross-flow instability modes is insignificant.