TITLE:
Study on Collision Process of Opposing Unsteady Supersonic Jets and Shock Waves
AUTHORS:
Sakira Uno, Hiroshi Fukuoka, Atsushi Suda, Ikurou Umezu
KEYWORDS:
Collision of Supersonic Jets, Shock Wave, Computational Fluid Dynamics, Laser Ablation
JOURNAL NAME:
Open Journal of Fluid Dynamics,
Vol.13 No.2,
May
25,
2023
ABSTRACT: Double pulsed-laser-ablation is a promising method to prepare nanoparticle composites. The backward movement of the plume after the collision with counter-propagating shock wave has been observed in experiments. In the present study, collision dynamics of the oppositely injected Si and Ge jets into a He background gas was numerically calculated as a simulation for double pulsed-laser-ablation. The experimentally observed backward movement was reproduced. The effect of distance between two jet exits on the distance of backward movement of the jet, BL, after the collision with the counter-propagating shock front was calculated to discuss the collision dynamics and to optimize the target distance for the experiment. We found that BL does not decrease monotonically with increasing distance between two jet exits, but has a maximum value at a certain distance. This behavior is discussed by calculating the expansion dynamics of an individual jet. Shock wave grows with time at the initial stage of the jet expansion and then attenuates; the density just behind the shock front for individual jet has a maximum value at a certain time and position. BL has a maximum value when the densities just behind the shock fronts for the individual jets have maximum values. This result is important for designing the appropriate distance between the two jet exits, i.e., the distance between the targets of double pulsed-laser-ablation.