Numerical simulation of an idealised Richtmyer–Meshkov instability shock tube experiment

The effects of initial conditions on the evolution Richtmyer–Meshkov instability (RMI) at early to intermediate times are analysed, using numerical simulations an idealised version recent shock tube experiments performed University Arizona (Sewell et al. , J. Fluid Mech. vol. 917, 2021, A41). experimental results bracketed by performing both implicit large-eddy high-Reynolds-number limit as well direct (DNS) Reynolds numbers lower than those observed in experiments. Various measures mixing layer width $h$ known scale ${\sim }t^\theta$ late time, based plane-averaged turbulent kinetic energy and volume fraction profiles used explore $\theta$ compared with results. decay rate $n$ total fluctuating is also estimate a relationship that assumes self-similar growth layer. estimates for range between 0.44 0.52 each broadband perturbations considered good agreement Decomposing into separate bubble spike heights $h_b$ $h_s$ shows that, while bubbles spikes initially grow different rates, their rates $\theta _b$ _s$ have equalised end simulations. Overall, demonstrate important differences narrowband surface perturbations, persistent finite bandwidth layers evolving from perturbations. Good obtained quantities considered; however, show care must be taken when measurements velocity field infer properties concentration field.