381 / 2019-02-28 16:01:31

Numerical investigations of metal interface instability in cylindrical geometry

Interface instability,Cylindrical implosion

全体主题 > Interface Instabilities at Extremes

The perturbed interface between two different fluids will destabilize and grow when the interface is impacted by a shock wave or when the light fluid accelerates the heavy one. The former phenomenon is called Richtmyer-Meshkov instability (RMI), the latter one is called Rayleigh-Taylor instability (RTI). Both RMI and RTI are of importance in a variety of man-made and natural applications such as inertial confinement fusion (ICF), supersonic combustion, astrophysics (supernova), etc. These interface instabilities also happen in metals under the conditions of strong loading such as explosion, laser, etc. Unlike fluids the material strength of metals can serve to retard the perturbation growth.
In this report, the dynamical behavior of implosion instability on a steel/rubber interface under explosion loading in a cylindrical geometry is numerically investigated by using an in-house Euler code. Because of the convergent effect, both RMI and RTI occur in the implosion process. Before the focus-rebound shock wave arrives at the perturbed interface, the RTI accompany with RMI to advance the perturbation growth. After arrival of the focus-rebound shock wave, the RMI plays a crucial role. Afterwards, the effects of initial wavelength, amplitude of perturbation and the initial thickness of steel shell on the development of implosion instability are studied.