BOUNDARY-LAYER LINEAR-STABILITY USING A SYSTEM OF PARABOLIC EQUATIONS

The classical theory of laminar boundary layer linear stability assume s a quasi-parallel flow. This paper gives a first look at a new approa ch to this linear stability problem. Instead of solving an ordinary di fferential equation (the so-called ''Orr-Sommerfeld'' equation in the parallel theory), partial differential equations must be solved which are parabolic in the mean flow direction. Hence, from a global point o f view, we have a problem of variation instead of an eigenvalue proble m. The new approach is more flexible for an equivalent computing time. After describing the new approach, results obtained using it are comp ared with others from the classical theory, from direct numerical simu lation, and from experiment.