Time evolution of the shear layer of a supersonic axisymmetric jet

We used a two-laser two-detector experiment to investigate the temporal evolution of the mixing layer of a pressure matched supersonic jet at an exit Mach number of 1.5. discharging into still air, resulting in a convective Mach number of 0.7. The convective speed of the structures present in the flow was measured and compared with previous findings. Additional views of the mixing layer provided information on the three dimensionality of the mixing layer. We found that the structures travel with a velocity higher than the predicted velocity and they rotate as they progress downstream.