Shock-Wave/Boundary-Layer Interactions in Scramjet Intakes with Axisymmetric and Planar Isolators

The present study numerically investigates the shock-wave/boundary-layer interactions (SWBLIs) inside a scramjet intake at Mach 4.03. A 2D-planar and an axisymmetric intake are investigated using commercial code ANSYS-Fluent. The density gradient for intakes is computed to investigate and compare the shock cell structure and the separation bubble size. Besides, the velocity and pressure distributions are analyzed for planar and axisymmetric intakes. It is observed from the wall pressure data that the shock strength in the case of axisymmetric intake is lesser than the planar intake. Also, the interaction region in the axisymmetric intake is shifted further downstream with a progressive decrease in shock angle. The recirculation zone or the separation bubble size is minimal for the axisymmetric intake than for planar intake, resulting in higher effective mass flow into the combustion chamber. It can be observed that although the cowl surface experiences the maximum wall static pressure, the recirculation zone formed over the cowl surface is comparatively smaller than that of the ramp surface. The normalized total pressures at the isolator exit indicate that the axisymmetric intake is more efficient in conserving the flow energy than the planar intake. The temperature rise over the ramp surface is higher for planar intake; however, the temperature fluctuations over the ramp surface are more for axisymmetric intake.