The late-time development of the Richtmyer–Meshkov instability

Measurements have been made of the growth by the Richtmyer–Meshkov instability of nominally single-scale perturbations on an air/sulfur hexafluoride ~SF6) interface in a large shock tube. An approximately sinusoidal shape is given to the interface by a wire mesh which supports a polymeric membrane separating the air from the SF6. A single shock wave incident on the interface induces motion by the baroclinic mechanism of vorticity generation. The visual thickness d of the interface is measured from schlieren photographs obtained singly in each run and in high-speed motion pictures. Data are presented for d at times considerably larger than previously reported, and they are tested for self-similarity including independence of initial conditions. Four different initial amplitude/wavelength combinations at one incident shock strength are used to determine the scaling of the data. It is found that the growth rate decreases rapidly with time, dd/dt}t ~i.e., d }t), where 0.67&p&0.74 and that a small dependence on the initial wavelength l0 persists to large time. The larger value of the power law exponent agrees with the result of the late-time-decay similarity law of Huang and Leonard @Phys. Fluids 6, 3765–3775 ~1994!#. The influence of the wire mesh and membrane on the mixing process is assessed. © 2000 American Institute of Physics. @S1070-6631~00!00907-7#