Experimental Investigation of Sphere Slamming to Quiescent Water Surface-Pressure Distribution and Jetting Flow Field

Abstract

Sphere slamming pressures and corresponding jetting flow fields were studied in an experimental approach. Correlations between sphere impacting forces and jetting flow occurrences were explored. Pressure sensor was used to investigate the slamming pressures distributed around the sphere at five measuring points. The jetting flow fields were carried out using the bubble image velocimetry (BIV) technique. Time series jetting flow speeds were successfully examined. The pressures and jetting were studied in four various sphere impacting speeds as four cases. Five designed impacting angles which means impacting measuring point around sphere surface for sensor were conducted for each case. Maximum pressures happened at impacting measuring point of 0o. Maximum jetting flow speed traveled as the front of jetting fields. The pressures and jetting speeds was proportional to corresponding impacting speed. Control volume approach was suggested to examine the force transfer between slamming and jetting. The jetting forces were compared with the impacting forces with respect to increasing surface area of sphere under water. The jetting forces detected after maximum jetting speed were similar with the impacting forces. The jetting flow velocities were able to be estimated. Maximum evaluated jetting flow velocity happened immediately after slamming occurred.