Destabilization and breakup of a planar liquid stream assisted by a co-flowing turbulent gas stream

In a planar gas-liquid mixing layer the destabilization and breakup of the liquid stream is assisted by a co-flowing high speed turbulent gas stream. The velocity difference between the gas and the liquid streams triggers a shear instability at the interface, which develops into an interfacial wave moving downstream. In this study we focus on the effect of the inlet gas turbulence on the interfacial instability, spray formation, and two-phase turbulence statistics. Direct numerical simulations for different gas inlet turbulence intensity levels are performed. A digital filter approach is used to generate temporally and spatially correlated velocity fluctuations at the inlet. The gas-liquid interface is resolved by a volume-of-fluid method. The most unstable frequency is observed to increase significantly with the inlet gas turbulence intensity, which is in agreement with experimental observations.