The Richtmyer-Meshkov instability of a 'V' shaped air/helium interface subjected to a weak shock

- A novel method using the soap film technique is developed to create a discontinuous 'V' shaped air/ helium interface for Richtmyer-Meshkov instability (RMI) study.
- The reduction factor is applied to the linear model and the modified linear model is capable to predict the width growth rate of interface with high initial amplitudes.
- The initial growth rate of interface width is a non-monotonous function of the initial vertex angle, which is found for the first time in a heavy/light interface configuration.

The Richtmyer-Meshkov instability of a 'V' shaped air/helium gaseous interface subjected to a weak shock wave is experimentally studied. A soap film technique is adopted to create a 'V' shaped interface with accurate initial conditions. Five kinds of 'V' shaped interfaces with different vertex angles are formed to highlight the effects of initial conditions on the flow characteristics. The results show that a spike is generated after the shock impact, and grows constantly with time. As the vertex angle increases, vortices generated on the interface become less noticeable, and the spike develops less pronouncedly. The linear growth rate of interface width after compression phase is estimated by a linear model and a revised linear model, and the latter is proven to be more effective for the interface with high initial amplitudes. The linear growth rate of interface width is, for the first time in a heavy/light interface configuration, found to be a non-monotonous function of the initial perturbation amplitude-wavelength ratio.