On the Secondary Instability of the Most Dangerous Görtler Vortex
Recent studies have demonstrated the most unstable Görtler vortex mode is found in flows, both two and three-dimensional, with regions of (moderately) large body curvature and these modes reside within a thin layer situated at the base of the conventional boundary layer. Further work concerning the nonlinear development of the most dangerous mode demonstrates that the flow results in a self induced flow reversal. However, prior to the point at which flow reversal is encountered the total streamwise velocity profile is found to be highly inflectional in nature. Previous work then suggests that the nonlinear vortex state will become unstable to secondary, inviscid, Rayleigh wave instabilities prior to the point of flow reversal. Our concern is with the secondary instability of the nonlinear vortex states, which result from the streamwise evolution of the most unstable Görtler vortex mode, with the aim of determining whether such modes can induce a transition to a fully turbulent state before separation is encountered.
KeywordsRayleigh Wave Secondary Instability Secondary Mode Stream Wise Velocity NASA Langley Research
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- Balachandar, S, Streett, C. L., & Malik, M. R. 1992 Secondary instability in rotating disk flow J. Fluid Mech. 242 323Google Scholar
- Bassom, A.P. & Hall, P. 1991 Vortex instabilities in three- dimensional boundary layers: The relationship between Gortler and Crossflow vortices J. Fluid Mech. 232 647Google Scholar
- Denier, J.P. & Hall, P. 1991 On the nonlinear development of the most unstable Gortler vortex mode J. Fluid Mech., 246 1Google Scholar
- Hall, P. 1988 Nonlinear development of Gortler vortices in growing boundary layers J. Fluid Mech. 193 247Google Scholar
- Otto, S. R. & Bassom, A. P. 1993 Nonlinear development of viscous Gortler vortices in a three dimensional boundary layer Stud. AppL Math, in press Google Scholar
- Otto, S. R. & Denier, J. P. 1993 On the secondary instability of the most dangerous Gortler vortex (in preparation) Google Scholar
- Swearingen, J. D. & Blackwelder, R. F. 1987 The growth and breakdown of streamwise vortices in the presence of a wall J. Fluid Mech. 182 255Google Scholar