We carry out a systematic numerical stability analysis of ZND detonations of
Majda's model with Arrhenius-type ignition function, a simplified model for
reacting flow, as heat release and activation energy are varied. Our purpose
is, first, to answer a question of Majda whether oscillatory instabilities can
occur for high activation energies as in the full reacting Euler equations,
and, second, to test the efficiency of various versions of a numerical
eigenvalue-finding scheme suggested by Humpherys and Zumbrun against the
standard method of Lee and Stewart.
We investigate existence and stability of viscoelastic shock profiles for a
class of planar models including the incompressible shear case studied by
Antman and Malek-Madani.
For the two-dimensional Navier--Stokes equations of isentropic
magnetohydrodynamics (MHD) with $\gamma$-law gas equation of state, $\gamma\ge
1$, and infinite electrical resistivity, we carry out a global analysis
categorizing all possible viscous shock profiles. Precisely, we show that the
phase portrait of the traveling-wave ODE generically consists of either two
rest points connected by a viscous Lax profile, or else four rest points, two
saddles and two nodes.