Wave impact loads: The role of the flip-through

The impact of waves upon a vertical, rigid wall during sloshing is analyzed with specific focus on the modes that lead to the generation of a flip-through ?M. J. Cooker and D. H. Peregrine, "A model for breaking wave impact pressures," in Proceedings of the 22nd International Conference on Coastal Engineering ?ASCE, Delft, 1990?, Vol. 2, pp. 1473-1486?. Experimental data, based on a time-resolved particle image velocimetry technique and on a novel free-surface tracking method ?M. Miozzi, "Particle image velocimetry using feature tracking and Delaunay tessellation," in Proceedings of the 12th International Symposium on Applications of Laser Techniques to Fluid Mechanics ?2004??, are used to characterize the details of the flip-through dynamics while wave loads are computed by integrating the experimental pressure distributions. Three different flip-through modes are observed and studied in dependence on the amount and modes of air trapping. No air entrapment characterizes a "mode ?a? flip-through," engulfment of a single, well-formed air bubble is typical of a "mode ?b?" event, while the generation of a fine-scale air-water mixing occurs for a "mode ?c?" event. Upward accelerations of the flip-through jet exceeding 1500 g have been measured and the generation/collapse process of a small air cavity is described in conjunction with the available pressure time histories. Predictions of the vertical pressure distributions made with the pressure-impulse model of Cooker and Peregrine ?M. J. Cooker and D. H. Peregrine, "Pressure-impulse theory for liquid impact problems," J. Fluid Mech. 297, 193 ?1995?? show good agreement with the experimental data.