Growth of Richtmyer–Meshkov Instability in Water Tamped Copper

The Richtmyer–Meshkov instability (RMI) arises at an impulsively accelerated interface between two materials of different density. Previous work showed material strength at high strain-rates in solids can extracted from the amplitude and growth of the RMI spike in an untamped environment (metal-vacuum) and in a distended tamping media (metal-porous solid). Here, a bridge to understanding the nonlinear mechanical behavior of copper into a water is investigated experimentally and computationally. Data collected from the tamped liquid environment range in metal breakout pressures up to ten GPa. Results shows the RMI growth rate and profile are dependent on initial shock strength, as well as the nondimensional perturbation, with an initial Atwood number of −0.78. The oscillatory shock front in water is used to approximate the viscosity from a transient 1-D analytic approximation. The viscosity is found to be in agreement with other experimental work, however is not determined to be the only dissipative force in the experiment. Hydrocode simulations of our experiments show reasonable alignment with current and previously published work.