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978-3-8439-1266-2, Reihe Ingenieurwissenschaften
Experimental investigations of supersonic and hypersonic shock wave/turbulent boundary layer interactions
233 Seiten, Dissertation Universität Stuttgart (2012), Softcover, A5
Shock wave/turbulent boundary layer interactions occur in a large number of flow problems relevant for hypersonic flight, both in the external flow field around hypersonic vehicles and in the engine intake flow of supersonic and hypersonic propulsion systems.
The large pressure and heat loads occurring in association with shock-induced separation may destroy the vehicle structure, and the unsteadiness of the shock system makes the propulsion system design quite challenging. A thorough understanding of this type of flow field and its underlying mechanisms is therefore of great interest, especially in the hope for effective shock-induced separation control in the future.
This doctoral thesis contributes to the increased understanding of the flow physics of supersonic and hypersonic compression corner interactions. The mean flow topology and turbulence behavior across several different interaction flow fields was investigated with an experimental approach. Special attention was given to the turbulence production and amplification mechanisms along the interaction.
In the supersonic flow regime, an incipiently-separated 11.5° compression corner interaction at a Mach number of 2.54 and momentum thickness Reynolds number of 5400 was investigated. Turbulent fluctuations of the streamwise and wall normal velocity components and Reynolds stresses were measured with normal and inclined hot-wires.
An unequally strong amplification and subsequent decay of the different turbulent quantities across the interaction occurred. Based on the observed turbulence behavior and a correlation study between the mass flux across the boundary layer and the surface heat flux, a mechanism describing turbulence production along incipiently-separated compression ramp interactions was proposed.
In the hypersonic flow regime, two cases of shock wave/turbulent boundary layer interactions have been studied by means of Particle Image Velocimetry at a Mach number of 7.2 and a momentum thickness Reynolds number of 3500: an attached 8° compression corner interaction and a separated 33° compression corner interaction. The influence of separation on the turbulence behavior was described.
In addition, a separation control study with a two-row staggered array of microramp sub-boundary layer vortex generators was performed, where the influence of microramps was studied in hypersonic flow for the first time.