| avitation in hydraulic machinery and in marine applications produces noise, destructive erosion and loss of efficiency. Their fundamental mechanisms, particularly of erosive damage, are not well established. High molecular weight polymer solutions at drag-reducing concentrations substantially alter macroscopic cavitation behaviors such as the inception point, the noise spectrum and the rate of damage. Again, causes are poorly understood.;Detailed results on the bubble migration and deformation largely confirm and extend prior studies in quiescent water. Jet development and velocities of 110-180 m/s were observed, but the jet tip could not be reliably identified, indicating these and other investigators' jet velocities are lower bounds only. In shear flow, bubbles developed a substantial 'lean' in the downstream direction and apparently weaker jets developed at an angle. Otherwise, behavior vs. ;To examine the mechanisms underlying these phenomena, single vapor bubbles of up to 1 cm diameter were initiated by a laser pulse and photographed in collapse under 1 atm pressure near a solid wall. Experiments were conducted for... |
