Investigation of the double ramp in hypersonic flow using luminescent measurement systems

Compression ramp flows in supersonic and hypersonic environments present unique flow patterns for shock wave-boundary layer interaction studies. They also represent the generic geometry of two-dimensional inlets and deflected control surfaces for re-entry vehicles. Therefore, a detailed knowledge of the flow behaviour created by such geometries is critical for optimum design. The flow is made more complicated due to the presence of separation regions and streamwise Görtler vortices. The objective of the current research is to study the behaviour and characteristics of the flow over the double ramp model placed in hypersonic flow at freestream Mach number of 5. Three different incidence angles of 0°, −2°, and −4° are studied using colour Schlieren and luminescent paints consisting of anodized aluminium pressure-sensitive paint (AA-PSP) and the temperature-sensitive paint (TSP) technique. The colour Schlieren provides description of the external flow while the global surface pressure and temperature distribution is obtained through the AA-PSP and TSP methods. The TSP technique also proves that it is very effective in identifying the location and properties of the Görtler vortices; revealing the effect of incidence on the magnitude and pattern of Görtler vortices formed.

► Double ramp model in Mach 5 flow is studied using global pressure and temperature-sensitive paint at three incidences.
► Complicated flow patterns including three-dimensional effects are visualised and quantified.
► The surface temperature and Görlter vortices in the flow reattachment region are captured by TSP.
► Results show that heat flux increases and the size of the separation region reduces when the model incidence is decreased.
► Large spanwise variation of Stanton number is found on the second ramp due to the presence of Görlter vortices.