Experimental investigation on fluid kinematics and impact pressure of flat plate impacts on pure and aerated water

Abstract

This study aims to demonstrate the applications of existing techniques for water entry problems in quantifying the multiphase flow regions, and to perform an experimental investigation on pure and aerated water entry of a flat plate. Measured pressure, velocity field, and local aeration level were utilized to examine the fluid kinematics and dynamics. Maximum water speeds were measured up to 1.59C and 1.74C for pure and aerated water entry, respectively, with C being the impact speed. Three stages of pressure evolution were identified. The intensity of the oscillation after the shock load was found negatively correlated with aeration level. Impact coefficient up to 27.64 was observed at the center of the plate bottom for pure water entry. The pressure impulse of the shock load was found less dependent on aeration level. For the shock load in aerated water entry, the correlation of peak pressure and rise time of yields distributions similar to those for breaking wave impacts. At all measurement points, an inversely proportional trend appears in the correlation between estimated peak forces and local aeration levels.