Experimental Determination of the Growth Rate of Richtmyer-Meshkov Induced Turbulent Mixing after Reshock

摘要

The Richtmyer-Meshkov Instability (RMI) develops when a shock wave impulsively accelerates an initially perturbed interface between two gases of different density, promoting their mixing inside a delimited zone, hereafter denoted the mixing zone (MZ). This mixing is a key issue for inertial confinement fusion process. It also finds applications in many different scientific and engineering issues, e.g. in supernova explosion or supersonic combustion. In the context of inertial confinement fusion, the characterization of the RMI-induced mixing zone initiated by a shock and further amplified by a reshock is largely based on the temporal evolution of integral parameters such as the width of the MZ. This is classically achieved through shock tube experiments involving the time-resolved acquisition of Schlieren images. From the initial shock/interface interaction, the global evolution of the MZ growth rate is found to experience a succession of five consecutive phases: 1) linear increase, 2) asymptotic increase, 3) strong decrease (recompression of the MZ induced by the reshock), 4) linear increase, 5) asymptotic increase.