Weak foci in three‐dimensional linear shock waves and the stability of real shock waves

Caustics of weak shock waves

The caustics of weak shock waves are studied through matched asymptotic expansions. It is shown that these caustics are thinner and more intense than those of smooth waves with a comparable amplitude. This difference in scalings solves a paradox that would have the caustics of weak shock waves behave linearly, even though linear theory for discontinuous fronts predicts infinite amplitudes near ...

The focusing of weak shock waves

This paper reports an experimental investigation, using shadowgraphs and pressure measurements, of the detailed behaviour of converging weak shock waves near three different kinds of focus. Shocks are brought to a focus by reflecting initially plane fronts from concave end walls in a large shock tube. The reflectors are shaped to generate perfect foci, ar6tes and caustics. It is found that, nea...

Attenuation of Weak Shock Waves in Liquids

Nonlinear Fresnel diffraction of weak shock waves.

Fresnel diffraction at a straight edge is revisited for nonlinear acoustics. Considering the penumbra region as a diffraction boundary layer governed by the KZ equation and its associated jump relations for shocks, similarity laws are established for the diffraction of a step shock, an "N" wave, or a periodic sawtooth wave. Compared to the linear case described by the well-known Fresnel functio...

Stability and Dynamics of Viscous Shock Waves

We examine from a classical dynamical systems point of view stability, dynamics, and bifurcation of viscous shock waves and related solutions of nonlinear pde. The central object of our investigations is the Evans function: its meaning, numerical approximation, and behavior in various asymptotic limits.