MECHANICS OF DEEP-WATER PLUNGING-WAVE IMPACTS ON VERTICAL STRUCTURES

The pressures resulting from a critical case of plunging-wave impact on a vertical wall are examined. A deep-water wave breaking condition, with the crest elevation about a fifth of the mean water depth, has been considered. Two distinct scales of the pressure time histories, a slowly varying (in the range of the wave period) component in the order of stagnation pressure and a transient impact component with much higher pressures, have been identified and correlated to the incident wave kinematics. It is found that impact pressures can be approximately decomposed into a primary component associated with the overall wave evolution and a component influenced by the trapped air dynamics. These characteristics are comparable to those observed in shallow water-wave impact studies. The loads at the zone of impact are also found to be comparable if the span of impact and the local incident wave kinematics are comparable.