Terminal velocities and vortex dynamics of weakly compressible Rayleigh–Taylor Instability

Youlizi Zhou,Quanxi Xue,Yudong Pu,Shufan Zou,Hao Liu

doi:10.1063/5.0079996

Abstract

The evolution of Rayleigh–Taylor instability (RTI) for weakly compressible fluids was numerically simulated using the smooth particle hydrodynamics method. It was found that the speed of spikes and bubbles in most cases will reach a stable value, which is called terminal speed. The calculated terminal speed of the bubble was found to be systematically higher than the theoretical model based on the potential flow hypothesis. This deviation could be modified by including the vortex effect on the terminal speed of the bubble. A significant correlation between the bubble speed and the vorticity in the bubble head was found during the whole evolution of RTI. The analysis of the vortex dynamics in the bubble head region during the terminal speed stage shows that there is a balance between the baroclinic production, viscous dissipation, and convective transport of the vorticity.

Highlights

Rayleigh–Taylor Instability (RTI) is a hydrodynamic instability that occurs at the interface when the heavy fluid is on top of the light fluid under the gravity field or a light fluid accelerates a heavy fluid.1,2 It plays a significant role in natural and engineering situations with a wide range of temporal and spatial scales.3 For instance, the existence of Rayleigh–Taylor instability in inertial confinement fusion (ICF)4 can significantly reduce the implosion efficiency of the target,5 which makes it the most critical challenge in ICF
Combining Eqs. (26), (29), and (30), we propose that the vorticity modified theoretical model for bubble’s terminal speed should be calculated as ub
The terminal speed of bubbles and spikes of RTI and its corresponding vortex dynamics were studied with smoothed particle hydrodynamics (SPH) simulations in this work

Summary

Introduction

Rayleigh–Taylor Instability (RTI) is a hydrodynamic instability that occurs at the interface when the heavy fluid is on top of the light fluid under the gravity field or a light fluid accelerates a heavy fluid. It plays a significant role in natural and engineering situations with a wide range of temporal and spatial scales. For instance, the existence of Rayleigh–Taylor instability in inertial confinement fusion (ICF) can significantly reduce the implosion efficiency of the target, which makes it the most critical challenge in ICF. Rayleigh–Taylor Instability (RTI) is a hydrodynamic instability that occurs at the interface when the heavy fluid is on top of the light fluid under the gravity field or a light fluid accelerates a heavy fluid.. Rayleigh–Taylor Instability (RTI) is a hydrodynamic instability that occurs at the interface when the heavy fluid is on top of the light fluid under the gravity field or a light fluid accelerates a heavy fluid.1,2 It plays a significant role in natural and engineering situations with a wide range of temporal and spatial scales.. The existence of Rayleigh–Taylor instability in inertial confinement fusion (ICF) can significantly reduce the implosion efficiency of the target, which makes it the most critical challenge in ICF It appears in the evolution of astrophysical systems, such as supernova explosions and solar corona.. The latest broadest overview of this subject is summarized by Zhou.

Methods

Results

Conclusion