Oscillating buoys are used to capture wave energy in point-absorbing wave energy converters, and they are also subjected to wave slamming while working. The loads generated by wave slamming may cause damage to wave energy converters. It's particularly important to take wave slamming phenomena into consideration during the design process of wave energy converters, especially the buoys. Experimental method is adopted to study the wave slamming pressure characteristics of oscillating buoys by changing wave parameters. According to the test results, it is found that: (1) The bottom slamming and side slapping pressure of the buoy is significantly greater than other conditions when the period is about 1.5 s. (2) As the wave height increases, the position where the buoy is slammed moves from outside to inward in the radial direction on the bottom. (3) Side slapping is the main form of wave slamming on the buoy. The slapping pressure is much greater than bottom slamming and overtopping slamming. The effect of overtopping slamming only exists when the wave height is large.
Wave slamming phenomena happen commonly during the operation of all marine engineering structures. And there is no exception for wave energy converters. As an important part of the energy harvesting system of a point-absorbing wave energy converter, the reliability of the oscillating buoys determines the lifetime of the entire wave energy converter. The slamming loads may reduce the fatigue strength of the buoys. Therefore, studying the wave slamming characteristics of the buoy is of great significance to the design reliability of the point-absorbing wave energy converter.
The wave slamming phenomena of marine structures have been studied for decades (Wang and Shi, 2008). Pioneering theoretical method is the slamming load calculation formula based on the momentum theorem proposed by von Karman (1929), and Wagner (1932) proposed the theory of flat plate fitting as a matching correction method based on the von Karman model. Because the theoretical method has made a lot of simplifications, it is subject to many restrictions in actual engineering application, while the experimental method has been applied more (Liu et al., 2018).
