Naslov
Laser generated Richtmyer-Meshkov instability and nonlinear wave paradigm in turbulent mixing : I. Central region of Gaussian

Autori
Lugomer, Stjepan

Izvornik
Laser and particle beams (0263-0346) 34 (2016), 4; 687-704

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Laser ablation ; Richtmyer-Meshkov instability ; Turbulent mixing ; Jet-spike breakup ; Wave-vortex phenomena ; Line solitons ; Horseshoe solitons ; Kadomtsev-Petviashvili equation

Sažetak
A three-dimensional (3D) Richtmyer-Meshkov instability (RMI) was generated on metal target by the laser pulse of Gaussian-like power profile in the semiconfined configuration (SCC). The SCC enables the extended lifetime of a hot vapor/plasma plume above the target surface as well as the fast multiple reshocks. The oscillatory pressure field of the reshocks causes strong bubble shape oscillations giving rise to the complex wave-vortex phenomena. The irregularity of the pressure field causes distortion of the shock wave front observed as deformed waves. In a random flow field the waves solidified around the bubbles form the broken “egg-karton” structure - or the large scale chaotic web. In the coherent flow field the shape oscillations and collapse of the large bubbles generate nonlinear waves as the line- and the horseshoe solitons. The line solitons are organized into a polygonal web, while the horseshoe solitons make either the rosette-like web or appear as the individual parabolic-like solitons. The configurations of the line solitons are juxtapositioned with solitons simulated by the Kadomtsev-Petviashvili (KP) equation. For the horseshoe solitons it was mentioned that can be obtained by the simulation based on the cylindrical Kadomtsev-Petviashvili (cKP) equation. The line and the horseshoe solitons represent the wave-vortex phenomena in which the fluid accelerated by the shock and exposed to a subsequent series of fast reshocks follows more complex scenario than in the open configuration. The RMI environment in the SCC generates complex fluid dynamics and the new paradigm of wave vortex phenomena in turbulent mixing.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
Published by Cambridge University Press

POVEZANOST RADA