The Growth of Goertler Vortices in Compressible Boundary Layers


Book Description

The linear instability of Goertler vortices in compressible boundary layers is considered. Using asymptotic methods in the high wavenumber regime, it is shown that a growth rate estimate can be found by solving a sequence of linear equations. The growth rate obtained in this way takes non-parallel effects into account and can be found much more easily than by ordinary differential equation eigenvalue calculations associated with parallel flow theories. Hall, Philip and Malik, Mujeeb R. Langley Research Center NASA-CR-178360, ICASE-87-46, NAS 1.26:178360 NAS1-18107; RTOP 505-90-21-01







NASA Technical Paper


Book Description







Secondary Instabilities of Görtler Vortices in High-Speed Boundary Layers


Book Description

This thesis first reveals the mechanism of Görtler instabilities and then demonstrates how transitions at hypersonic flows can be effectively controlled (either promoted or suppressed) with Görtler or Klebanoff modes. It focuses on understanding and controlling flow transitions from mild laminar to fully turbulent flows at high speeds—aspects that have become crucial at the dawn of an incredible era, in which hypersonic vehicles are becoming available. Once this occurs, it will be possible to travel from Beijing to Los Angeles within just 2 hours, and we will all live in a genuinely global village—and not just virtually, but physically. Görtler instabilities have often been used to promote flow transition in hypersonic vehicles. However, how Görtler instabilities are excited and how they evolve in hypersonic flows are questions that have yet to be answered.