Study on the magnetic field suppression characteristics in the interaction process of shock save and light gas cylinder

Abstract

Based on ideal compressible magnetohydrodynamics (MHD) equations, the interface instability induced by the interaction between planar shock wave and the lightw gas (Helium) cylinder under the influence of the magnetic field with different directions was investigated numerically using the CTU(Corner Transport Upwind)+CT (Constrained Transport) algorithm. The numerical results elucidate the evolution of flow field characteristics and wave structures with and without magnetic field. Moreover, we examine the impact of the magnetic field direction on the characteristic scales (including the length, height and width of the central axis of gas cylinder), as well as the volume compressibility. Then, the study delves into the influence mechanism of the magnetic field direction on interface instability by integrating analyses of the circulation, energy, velocity and magnetic force distribution within the flow field. Figure 14 is the core of this paper, which explores the suppression mechanism of interface instability by magnetic field force. The results illustrate that magnetic pressure plays a crucial role in driving vorticity away from the interface, thereby reducing its deposition on the density interface. Simultaneously, it adheres to the divided vortex layer, thereby effectively isolating the influence of Richtmyer-Meshkov instability on the interface. On the other hand, the magnetic tension adheres to the separated vortex layer, and its direction opposes the vorticity generated by the shear of interface velocity. This action effectively suppresses the Kelvin-Helmholtz instability and the rolling-up of vortices on the density interface. Additionally, under the control of a longitudinal magnetic field, the magnetic tension acts in the opposite direction to the central jet, and effectively suppresses the development of Rayleigh-Taylor instability.