Primary Breakup Instability of Liquid Jet in Crossflow

The liquid jet in crossflows (LJICF) has been analyzed using the compressible Volume of Fluid-Lagrangian Particle Tracking (VOF-LPT) coupled solver for the instabilities that result in the primary breakup. It is understood that the dominant force driving the instabilities change with the Weber number and momentum flux ratio. The Kelvin-Helmholtz (KH) instability is found to be prevalent at low momentum flux ratio, whereas the Rayleigh-Taylor (RT) instability is dominant at higher values. In the present work, the instability causing the primary breakup is analyzed for a range of Weber numbers and momentum flux ratios where the breakup is predominantly caused by either KH or RT instability. It is observed that the transition from KH waves to RT waves happens for the momentum flux ratio values ranging from 20 to 50. Also, the lower Weber number cases appear to show the domination of long KH waves on the liquid jet column with negligible turbulence.