Deep-water plunging wave pressures on a vertical plane wall

Abstract

A systematic study is presented of pressures on a vertical wall resulting from controlled, plunging waves in deep water. Simultaneous measurements of the kinematics and dynamics of impact show that impact occurs through the focusing of the incident wave front onto the wall, trapping some amount of air in the process. Impact leads to high impulsive pressures, and the dynamics of trapped air can lead to even higher pressures coupled with pressure oscillations. Impact pressures may be decomposed into contributions due to the hydrodynamics of impact and the trapped-air dynamics. The latter is still poorly understood and the extrapolation of measured pressure maxima from laboratory scales to prototype scales is at this stage impossible. Overall, the characteristics and distributions of impact pressures depend significantly on the wall location relative to the wave-breaking location. However, at each wall location, identical incident wave conditions could yield significantly different impact pressures, mainly because of the randomness of the trapped-air dynamics during wave breaking.