Goertler Vortices In Growing Boundary Layers The Leading Edge Receptivity Problem Linear Growth And The Nonlinear Breakdown Stage

Goertler Vortices in Growing Boundary Layers: The Leading Edge Receptivity Problem, Linear Growth and the Nonlinear Breakdown Stage

Goertler Vortices in Growing Boundary Layers

Goertler vortices are thought to be the cause of transition in many fluid flows of practical importance. A review of the different stages of vortex growth is given. In the linear regime, nonparallel effects completely govern this growth, and parallel flow theories do not capture the essential features of the development of the vortices. A detailed comparison between the parallel and nonparallel theories is given and it is shown that at small vortex wavelengths, the parallel flow theories have some validity; otherwise nonparallel effects are dominant. New results for the receptivity problem for Goertler vortices are given; in particular vortices induced by free stream perturbations impinging on the leading edge of the walls are considered. It is found that the most dangerous mode of this type can be isolated and it's neutral curve is determined. This curve agrees very closely with the available experimental data. A discussion of the different regimes of growth of nonlinear vortices is also given. Again it is shown that, unless the vortex wavelength is small, nonparallel effects are dominant. Some new results for nonlinear vortices of 0(1) wavelengths are given and compared to experimental observations. Hall, Philip Unspecified Center...

On the Spatial Evolution of Long-wavelength Goertler Vortices Governed by a Viscous-inviscid Interaction