Mixing efficiency across Rayleigh-Taylor and Richtmeyer-Meshkov fronts

摘要

Mixing generated by gravitational acceleration and the role of local turbulence measured through \udmultifractal methods is examined in numerical experiments of Rayleigh-Taylor and Richtmyer-Meshkov driven\udfront occurring at density interfaces. The global advance of the fronts is compared with laboratory experiments\udand Nusselt and Sherwood numbers are calculated in both large eddy simulation (LES) and kinematic simulation \udKS models. In this experimental method, the mixing processes are generated by the evolution of a discrete set of forced\udturbulent plumes. We describe the corresponding qualitative results and the quantitative conclusions based on measures of the \uddensity field and of the height of the fluid layers. We present an experimental analysis to characterize the partial mixing process.\udThe conclusions of this analysis are related to the mixing efficiency and the height of the final mixed layer as functions \udof the Atwood number, which ranges from 9.8×10-3 to 1.34×10-1