CAVITIES FORMED ON LIQUID SURFACES BY IMPINGING GASEOUS JETS.

Assuming the jet mixes turbulently with the surrounding atmosphere, the stagnation pressure corresponding to the centerline conditions of the jet at a point of the cavitys maximum depth, i.e., height of mozzle above liquid plus cavity depth, was equated with the hydrostatic pressure at the cavitys bottom allowing a determination of the depth. The diameter of the cavity or maximum width was predicted for axisymmetric and two-dimensional jets. Prediction of minimum jet pressure required to induce liquid spray was made by an equilibration of surface tension, gravity, and drag forces. Experimental tests of air impinging on both water and wet cement were performed and analyzed along with the results of air impingement on various other liquids. The experimental cavities formed on the water were extremely irregular, however, time exposure photographs allowed detailed inspection of the steady state shape of these cavities. Cavities were also formed on wet cement and by allowing the cement to set with the air jet still impinging, detailed measurements could be made of the solidified cavity shape. Streamline tests were then made within and above some of these cavities. Author