INSTABILITY OF A CONTACT SURFACE DRIVEN BY A NONUNIFORM SHOCK-WAVE

Stability of a uniform contact surface is investigated in the case whe n a nonuniform shock wave passes through the surface, The nonuniform s hock is, generated by a rippled piston that moves with constant veloci ty. The amplitude of the shock oscillates and decreases as it propagat es. A uniform contact surface is found to be unstable after the nonuni form shock passes across it. The growth rate depends sensitively on th e phase of the oscillating shock wave at the time when the shock hits the contact surface. The physical mechanism of the instability is qual itatively discussed. The linear and nonlinear evolutions of the instab ility are studied. In particular, the dependence of the linear case on the Atwood number for a weak shock is investigated. Properties of thi s stability are found to exhibit differences from those of the standar d Richtmyer-Meshkov instability in both the linear and nonlinear cases .