The phase effect on the Richtmyer–Meshkov instability of a fluid layer

Abstract

Shock-induced finite-thickness fluid layer evolution is investigated numerically and theoretically. Specifically, two-dimensional helium layers consisting of two interfaces owning diverse perturbation phases are considered to explore the interface-coupling on the Richtmyer–Meshkov instability (RMI). A general linear model is first established to quantify the phase effect on the RMI of the two interfaces of an arbitrary fluid layer. The linear model is validated with the present numerical results. As the phase difference between the two interfaces' perturbations increases, the linear amplitude growth rates of the two interfaces are larger. The influences of diverse parameters on the interface-coupling are concerned. Moreover, the nonlinearity of the RMI of the two interfaces is dependent on the phase difference. Finally, spectrum analysis is performed to investigate the phase effect on perturbation growths of the first three-order harmonics of the two interfaces.