Flow features resulting from shock wave impact on a cylindrical cavity
Journal of Fluid Mechanics
School of Mechanical, Industrial and Aeronautical Engineering, University of the Witwatersrand, Johannesburg 2050, South Africa; School of Aerospace, Civil, and Mechanical Engineering, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia
The complex flow features that arise from the impact of a shock wave on a concave cavity are determined by means of high-speed video photography. Besides additional information on features that have previously been encountered in specific studies, such as those relating to shock wave reflection from a cylindrical wall and those associated with shock wave focusing, a number of new features become apparent when the interaction is studied over longer times using time-resolved imaging. The most notable of these new features occurs when two strong shear layers meet that have been generated earlier in the motion. Two jets can be formed, one facing forward and the other backward, with the first one folding back on itself. The shear layers themselves develop a Kelvin-Helmholtz instability which can be triggered by interaction with weak shear layers developed earlier in the motion. Movies are available with the online version of the paper. © Cambridge University Press 2007.
Cylinders (shapes); Imaging techniques; Jets; Numerical methods; Shear flow; Shock waves; Flow features; Kelvin-Helmholtz instability; Video photography; Fluid structure interaction; Cylinders (shapes); Fluid structure interaction; Imaging techniques; Jets; Numerical methods; Shear flow; Shock waves; cylinder; fluid flow; imaging method; Kelvin-Helmholtz instability; photography; shear flow; shock wave