Trajectories of Air-Water Bubbly Jets in Crossflows

Trajectories of bubbly jets in crossflows by injecting air-water mixtures vertically through a circular nozzle were experimentally studied. Bubbles separated from the water jets in strong crossflow, similarly to that of multiphase plumes in crossflow reported in the literature. Based on dimensional analysis, a semiempirical relation was developed to predict the separation height for bubbly jets with strong initial momentum. Centerline trajectories of both the water and air phases of bubbly jets were examined. After the separation, the air-phase centerlines can be treated as straight lines. The spreading rates of half-thickness and half-width of the air phase were studied along the airphase centerline. They decreased substantially after the bubble separation from the water jets and their terminal values appeared to increase with mean bubble diameter. (C) 2014 American Society of Civil Engineers.