39 research outputs found
Linear relaxation to planar Travelling Waves in Inertial Confinement Fusion
We study linear stability of planar travelling waves for a scalar
reaction-diffusion equation with non-linear anisotropic diffusion. The
mathematical model is derived from the full thermo-hydrodynamical model
describing the process of Inertial Confinement Fusion. We show that solutions
of the Cauchy problem with physically relevant initial data become planar
exponentially fast with rate s(\eps',k)>0, where
\eps'=\frac{T_{min}}{T_{max}}\ll 1 is a small temperature ratio and
the transversal wrinkling wavenumber of perturbations. We rigorously recover in
some particular limit (\eps',k)\rightarrow (0,+\infty) a dispersion relation
s(\eps',k)\sim \gamma_0 k^{\alpha} previously computed heuristically and
numerically in some physical models of Inertial Confinement Fusion
On the Use of the HLL-Scheme or the Simulation of the Multi-Species Euler Equations
The HLL approximate Riemann solver is a reliable, fast and easy to implement tool for the under-resolved computation of inviscid flows. When applied to multi-species flows, it generates pressure oscillations at material interfaces. This is a well-known behaviour of conservative solvers and has been addressed as a problem by several authors before. We show that for this particular solver, the generation of pressure oscillations can be desired and is consistent with the underlying physics