Richtmyer-Meshkov Instabilities
Richtmyer-Meshkov instability is a phenomenon observed when
a density stratified interface is accelerated impulsively. This
occurs in fields as diverse as supernovae and supersonic combustion.
My Work
Richtmyer-Meshkov instabilities are a good illustration of a
vorticity driven phenomenon. As the shock traverses the planar
density interface, the misalignment of the density and pressure
gradient result in the deposition of vorticity. This evolves and
finally collapses into a patch, driving the flow and distorting
the interface.
- Vorticity.
Slow-fast interactions (where the shock travels from a denser
medium to a rarer one) illustrate complex irregular shock refractions
at the interface. The transmitted (precursor) shock refracts back
into the denser medium and modies the incident shock, thus forming a
triple - shock system. The shadowgraph illustrates the shock system.
- Shock system ( A classic
Twin Mach Refraction system ).
As the vorticity evolves and rolls up into a
big wall vortex,
turbulent mixing occurs at the interface, leading to a mixing
region. This mechanism has been suggested as potential fuel -
air mixing method in supersonic combustion. This is shown in
the density map of the region.
- Density .
Future Work
I'll be investigating the roll up of the vortex sheet and
building reduced models of this interaction. For slow-fast
interfaces, this will necessarily have to be numerical, but
a purely analytical model may be possible in fast-slow cases.
Some Related Animations And Links
An
animation showing the evolution of the interface.
Juxtaposing different diagnostics.
A high resolution version.
Go to interactions at circular interfaces .
jaray@www.caip.rutgers.edu