Sharp interface limit for compressible non-isentropic phase-field model

Abstract

In this paper, the sharp interface limit for the compressible non-isentropic Navier-Stokes/Allen-Cahn system is derived by the method of matched asymptotic expansion. We show that the leading order problem satisfies the compressible Navier-Stokes equations with the interface being a free boundary. We discuss two cases in terms of different phase field diffusion coefficients. One is $M_{\epsilon}=O(1)$ and $M_{\epsilon}=O(\frac{1}{\epsilon})$, where $\epsilon$ is the interface thickness. We have observed that the velocity and the temperature of the compressible immiscible two-phase fluids continuously through the interface. There is a jump for the tension tensor at the interface, this jump depends on the surface tension and the mean curvature of the interface. In particular, for the first case $M_{\epsilon}=O(1)$, no matter how the density changes through the interface, the velocity of the interface in the normal direction is the same as the normal velocity of the fluid along the interface. But for the second case $M_{\epsilon}=O(\frac{1}{\epsilon})$, This phenomenon cann't occur where the density passes continuously through the interface.In fact, on this part of the interface, the normal velocity of the interface is determined by the mean curvature of the interface, the velocity and the density of the compressible immiscible two-phase fluids. That's where the phase transition happens.