Simulation and analysis of rarefied parallel interacting sonic jets

The interaction effects between two rarefied parallel sonic jets are studied. When the flow is in the free or near-free molecular regime, in which case the interaction effects are weak, the density profile of the flow field can be approximated by the summation of the density profiles of the individual jets using an asymptotic model developed by Ashkenas and Sherman.¹ This explains the existence of the self-similarity of the flow field for the density profile, which was discovered by Zhu and Oagum.^2-4 For the flow in the continuum or nearcontinuum regime, in which case the interaction effects are strong, self-similarity does not hold and interaction shock waves are formed. To analyze the influence of the interaction shock wave, a modified Penetration Knudsen Number has been introduced. It is shown that the existence of the interaction shock wave significantly decreases molecular penetration. This effect is shown in the density profiles from the DSMC calculation. The translational non-equilibrium in the interaction region is also analyzed from the OSMC results.