| A curved shock of general shape in hypersonic flow generates vorticity, so that a shear layer is formed in the flow downstream of the shock. The parameters affecting the distribution of vorticity in the shear layer are identified. Experiments aimed at determining the preferred wavelength of structures that develop in these flows are carried out in the T5 Hypervelocity Shock Tunnel. To visualize these structures, a new technique using streaklines is developed. The results are compared with numerical simulations of perfect-gas flows.; The numerical study also points to a flow regime, as the Newtonian limit is approached, where the instability of the shear layer is such that the shock becomes distorted. A series of experiments aimed at investigating flows approaching this limit is performed, using the T5 Light Gas Gun facility, and confirms the existence of this new regime. |
