Research Projects

Shock Wave Boundary Layer Interaction (SWBLI) is inevitable in the case of supersonic and hypersonic flows. SWBLI is typically encountered in the intake of Scramjet inlet and isolator, vehicle surface geometry changes, control surface deflections, at the junction of body-wing of aircraft etc. SWBLI induces local pressure gradient which can cause either local thickening of the boundary layer or flow separation, depending on the shock wave strength. In the case of flow separation, the local flow field is complex; consisting of a separation bubble, separation shock, shear layers and re-attachment shock. An important aspect of separated flow field is the associated unsteadiness. SWBLI can induce significant unsteady local pressure and heat transfer loads which will not only modify the flow downstream but can also cause significant structural damage leading to failure of the vehicle. Therefore, a complete understanding of the SWBLI region and the associated unsteadiness is essential before designing any mechanism to control/ mitigate its effects. 2-D SWBLI has been studied in detail at supersonic speeds and to some extent at hypersonic speeds, however 3-D SWBLI flowfields are relatively less explored at hypersonic speeds. The flow topology for a 3-D field is different from a 2-D Field. Different canonical configurations generating 3-D SWBLI has been investigated in the past. Similar to 2-D the flowfield is fluid dynamically rich with separation bubble, shear layer formation etc. Scientific Objective: 3-D interaction and associated unsteadiness are mainly studied for incoming turbulent boundary layer cases as most of these studies were carried out in supersonic wind tunnel with the protuberance mounted on the tunnel test section walls. Laminar interaction is yet to be explored. In this backdrop, the proposed research aims to study 3-D SWBLI interactions occurring in a Laminar hypersonic boundary layer and to characterise the associated unsteadiness in the interaction as well as the aft body wake region flow. The experimental campaign will involve unsteady surface pressure measurements, Schlieren flow visualization and Laser scattering technique, which will give details at each span wise location (events happening in a plane) a novel technique which will be implemented in the proposed research work for hypersonic flows in particular. This will significantly enhance our knowledge on 3-D SWBLI and unsteady wake flows which will help us in the proper design of hypersonic vehicles