ILASS Americas, 29 th Annual Conference on Liquid Atomization and Spray Systems, Atlanta, GA, May 15-18, 2017 Temporal Evolution of Liquid Jets in Supersonic Crossflows Kuo-Cheng Lin* Taitech, Inc. Beavercreek, Ohio 45430 Timothy Ombrello and Campbell Carter Air Force Research Laboratory, Aerospace Systems Directorate Wright-Patterson AFB, Ohio 45433 Ming-Chia Lai Wayne State University Detroit, Michigan 48202 Abstract Temporal evolution and structures of both pure- and aerated-liquid jets injected into a Mach 1.94 crossflow environ- ment were explored with high-speed shadowgraph imaging and phase Doppler particle analysis (PDPA). Water and nitrogen at the desired flow rates were injected through an aerated-liquid injector equipped with an exchangeable nozzle adaptor. The nozzle configuration with a constant-diameter passage was selected for liquid delivery at two intrusion depths from the tunnel floor. It was found that formation and propagation of protrusion structures located on the windward side of the initial spray columns, generated by either pure- or aerated-liquid jets, play important roles in initial liquid column breakup and eventual plume formation. In a pure-liquid jet, the protrusion structure is generated from surface wave growth on a solid liquid column and typically propagates downstream at a lower speed. In an aerated-liquid jet, the protrusion structure is generated from the thin liquid film of the spray cone and propagates downstream at a higher speed, due to the higher plume penetration. The intrusion injector can enhance plume pene- tration with respect to the nozzle exit plane. Spray penetration heights were also measured from the average shadow- graph images for correlation development. PDPA measurements show that the injected liquid mass is mainly distrib- uted within a kidney-shaped domain located near the periphery of the plume, which is above the penetration heights characterized by the shadowgraph images. __________________________________________ * Corresponding author, Kuocheng.Lin.ctr@us.af.mil