The evolution of the three-dimensional planar Richtmyer-Meshkov (RM) instability
during a two shock wave interaction (i.e., reshock) is investigated by means of comparing
numerical simulations and analytical modelling with experimental results of
low Mach numbers (M < 1.5) and fairly high Atwood numbers (A ∼ 0.7). The study
discusses and analyses the differences in the evolution of the mixing zone for two different
types of initial perturbations, namely, multi-mode random initial perturbation
with a narrow or wide bubble size distribution. More specifically, the study is focused
on the agreement between numerical simulations and experiments performed with
an unknown random initial perturbation. Using a large set of experimental results
with different reshock arrival times and Mach numbers, the numerical simulations
results are compared to the experimental results for a variety of different scenarios.
This methodology allows a constrained comparison, while requiring good agreement
for all cases. A comprehensive parametric study is conducted, examining the evolution
of the mixing zone (MZ) for different initial amplitudes and wavelengths. It is
found that in order to achieve a good agreement, the numerical simulation must be
performed using a wide enough initial spectrum, which enables a dominant, efficient
bubble merging process to take place within the MZ. The numerical simulation results
are compared to a model, based on classic single bubble RM evolution formulation,
combined with high amplitude effects consideration and phase reversal treatment in
case of heavy to light reshock passage. The model is also extended for the case of
multi-mode fronts, accounting for a bubble merging process, determining that the MZ
evolution after the reshock can be classified with high confidence as governed by an
inverse cascade bubble merger, approaching self-similarity