Richtmyer-Meshkov instability on two-dimensional multi-mode interfaces

Shock-tube experiments on eight kinds of two-dimensional multi-mode air-SF interface with controllable initial conditions are performed to examine the dependence of perturbation growth on initial spectra. We deduce and demonstrate experimentally that the amplitude development of each mode is influenced by the mode-competition effect from quasi-linear stages. It is confirmed that the mode-competition effect is closely related to initial spectra, including the wavenumber, the phase and the initial amplitude of constituent modes. By considering both the mode-competition effect and the high-order harmonics effect, a nonlinear model is established based on initial spectra to predict the amplitude growth of each individual mode. The nonlinear model is validated by the present experiments and data in the literature by considering diverse initial spectra, shock intensities and density ratios. Moreover, the nonlinear model is successfully extended based on the superposition principle to predict the growths of the total perturbation width and the bubble/spike width from quasi-linear to nonlinear stages.

Automated summary

The study conducted shock-tube experiments on two-dimensional multi-mode air-SF interfaces with controllable initial conditions, revealing the significant impact of initial spectra on perturbation growth. It was found that the mode-competition effect is closely related to initial spectra, and a nonlinear model based on initial spectra was established to predict the amplitude growth of individual modes. The nonlinear model was validated by experiments and data, and successfully extended to predict the growths of total perturbation width and bubble/spike width.