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 $1500\mathrm{g}$ 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.

This letter deals with the sea state monitoring starting from marine radar images in the X-band. For such a topic, one of the key factors affecting the reliability of reconstruction procedure is the determination of the equivalent surface current that also accounts for the velocity of a moving ship. In this letter, we propose a method to evaluate the surface current, particularly for large values. The reliability of the proposed procedure is shown by a numerical analysis with synthetic data. Subsequently, we present some preliminary results with experimental data collected by a radar on a moving ship.

The flip-through phenomenon has been observed in several conditions characterized by a steep wave approaching a vertical wall (Peregrine 2003). One of the cases where this phenomenon has been observed and studied experimentally is the sloshing in a partially filled tank. This case has been described in Lugni et al. (2006) and in Faltinsen and Timoka (2009). Those experiments detail the features of the flip-through dynamics with an ad hoc distributions of miniaturized pressure sensors and with the records of a fast video-camera. Here, the same flow conditions have been reproduced numerically with an improved SPH method (cSPH), i.e. with MLS integral interpolators (Fries and Matthies 2003). This allows to solve the Euler equations in the case of free surfaces impacting at a wall. The extremely intense local features of the phenomenon highlight the capabilities and limits of the numerical algorithms proposed.