Global stability of swept flow around a parabolic body: connecting attachment-line and crossflow modes

The global linear stability of a three-dimensional compressible flow around a yawed parabolic body of infinite span is Investigated Using all iterative eigenvalue method ill conjunction with direct numerical simulations. The computed global Spectrum shows all unstable branch consisting of three-dimensional boundary layer modes whose amplitude distributions exhibit typical characteristics of both attachment-line and crossflow modes. Ill particular, global eigenfunctions with smaller phase velocities display a more Pronounced structure near the stagnation line, reminiscent of attachment-line modes while still featuring strong crossflow vortices further downstream. This analysis establishes a link between the two prevailing instability mechanisms Oil a swept parabolic body which, so far, have only been Studied separately and locally. A parameter Study shows maximum modal growth for a spanwise wavenumber Of beta=0.213%., suggesting a preferred disturbance length scale in the sweep direction.