Investigation of Gortler vortices in hypersonic flow using Quantitative Infrared Thermography (QIRT) and Tomographic Particle Image Velocimetry (Tomo-PIV)

Abstract

Aerodynamic heating is one of the driving aspects in hypersonic vehicle design. During take-off and re-entry, high heat loads are encountered for which the appropriate measures have to be considered. In particular during the re-entry phase, high maneuverability of the vehicle is preferred such that reusable (manned) spacecraft can land on conventional runways. Control devices are therefore a necessity to improve the maneuverability of the spacecraft. Consequently, the hypersonic flow behaviour around control flaps is thoroughly investigated over the last decades. Boundary layer separation/reattachment and shock wave interaction are general flow phenomena that occur in hypersonic double ramp flow. Furthermore, streamwise periodic counter rotating vortices (Gortler vortices) tend to grow in the boundary layer over the control surface. Gortler vortices are induced by the centrifugal forces associated with the change in direction of motion forced on the fluid by the concave geometry of the surface. Gortler vortices take the form of a striation pattern and considerably modify the heat flux and can cause spanwise heat transfer variations of 100%.