Experimental investigations of free-surface aeration in the developing flow of two-dimensional water jets

Turbulent water jets discharging into the atmosphere are often characterized by a substantial amount of free-surface aeration. The effects can be detrimental or beneficial, In any case, the knowledge of the air entrainment mechanisms is essential for an optimum design. New experimental data are presented in the developing flow region of two-dimensional water jets discharging into air. The results indicate that the air diffusion takes place rapidly downstream of the nozzle and it is nearly independent of the momentum transfer process. Further, the distribution of air bubble frequency may be related to the air content distribution by a parabolic relationship.