Preferential concentration in supersonic gas-particle two-phase transverse jets

The supersonic gas-particle two-phase transverse jet is a typical flow process in many applications, such as solid rocket scramjet. This study carried out experimental tests as well as Large Eddy Simulation (LES) to investigate the evolution process of transverse gas-particle two-phase jets in supersonic crossflow, especially focusing on the phenomena called preferential concentration. The simulation is based on the Eulerian-Lagrangian method, which successfully reproduces the characteristic phenomena observed in experiments. The particle cloud forms three different characteristic distribution patterns: tooth-like waves near the jet port, quasi-ordered structures near counter-rotating vortex pairs (CVP), and filamentous clouds in the upper part. The turbulence and small unstable shock play a suppressing role in mixing small-diameter particles, which tend to aggregate in regions of high density and low vorticity. Furthermore, it is found that there exists a specific range of particle sizes, as particles' sizes approach this specific range, the influence of compressibility of the airflow on particle distribution becomes increasingly prominent. Overall, this study shed some light on the understanding of the complex and intricate nature of the supersonic gas-particle two-phase transverse jet.