| Popis: |
We study the linear spatio-temporal stability characteristics of inflectional and non-inflectional parallel flows and towards this consider separated boundary layer flow (SBLF), plane Couette-Poiseuille flow (CPF) and Falkner Skan flow with Favourable Pressure Gradient (FSFPG) with the boundary moving opposite to bulk fluid motion. We compute the temporal growth rate (\(\omega _{o,i}\)) at the saddle point of the dispersion relation in a frame of reference moving in the streamwise direction at a constant speed V, and locate the leading and trailing edge velocities (\(V_{LE}\), \(V_{TE}\)) of the unstable wave packet for each of these flows. We show that their difference \(\Delta V = V_{LE}-V_{TE}\), taken as a measure of dispersion of the unstable wave packet and its dependence on Reynolds number (Re) show important features that differentiate spatio-temporal instability dynamics of inflectional and non-inflectional flows. |
