Primary Breakup of Liquid Jet in Supersonic Crossflows Modeled Using A Mass-Conserving Level Set Scheme*

A good number of studies has been conducted to model breakup of liquid jet by subsonic airflows. However, itssupersonic equivalent has not received enough attention due to computational complexities involved. In this work, we formulate a mass-conserving level set scheme that is suitable for high-speed applications. Since the interface between the supersonic gas flow and the subsonic liquid flow is marked by a high-density ratio (of a thousand or more), the instabilities occurring at the interface need to be resolved with high accuracy. In our study, the gaseous region is compressible while the liquid region is assumed incompressible. The compressible domain has been resolved using a MUSCL based high resolution scheme that has a shock capturing ability. The incompressible domain is calculated with a pressure correction scheme to reduce computational costs. The level set method has been coupled with the volume of fluid method through a functional relationship between the level set and the volume of fluid functions. In this manner, mass is conserved while a sharp description of the interface is maintained. We present our results first in two dimensions and verify them by comparing with other numerical studies. Then we extend our model to three dimensions and validate our results against experimental findings.