Publications Details
A preliminary study of the longitudinal merging of instability wave packets and turbulent spots in a hypersonic boundary layer
Casper, Katya M.; Beresh, Steven J.
The longitudinal merging of wave packets and turbulent spots in a hypersonic boundary layer was studied on the nozzle wall of the Boeing/AFOSR Mach-6 Quiet Tunnel. Two pulsed glow perturbations were created in rapid succession to generate two closely spaced disturbances. The time between the perturbations was varied from run to run to simulate longitudinal merging. Preliminary results suggest that the growth of the trailing distur- bance seems to be suppressed by the presence of the leading disturbance. Conversely, the core of the leading disturbance appears unaffected by the presence of the trailing distur- bance and behaves as if isolated. This result is consistent with low-speed studies as well as DNS computations of longitudinal merging. However, the present results may be influ- enced by the perturber performance and therefore further studies of longitudinal merging are necessary to confirm the effect on the internal pressure structure of the interacting disturbances.