H. Oertel et J. Delfs, MATHEMATICAL-ANALYSIS OF AREAS OF FLOW SU BJECTED TO FRICTION, Zeitschrift fur angewandte Mathematik und Mechanik, 75(7), 1995, pp. 491-505
The Basics of the description of wave packets generated by localized d
isturbances in an unstable three-dimensional compressible flow are pre
sented. The classification into convectively and absolutely unstable b
ehaviour is explained as well as the mathematical criteria (collision-
, saddlepoint criterion) for the distinction of these two phenomena. T
he worked out stability analyses of crossflow- and Tollmien-Schlichtin
g instability on a swept wing both show convectively unstable behaviou
r. The amplification of the crossflow instability reacts strongly upon
small changes in si veep angle near a wing sweep of about 20 degrees.