Impact pressure distribution and characteristics of breaking wave impact on a monopile

Abstract

A laboratory model study is performed to investigate the characteristics of wave impact pressures on a monopile substructure for offshore wind turbines subjected to breaking waves in intermediate water depth. Laboratory experiments are conducted in a 30m long, 2m wide and 1.8m deep wave flume. Breaking wave was generated by focusing the wave energy from a wave group at a pre-defined time and space in the laboratory flume. High-resolution impact measurements are carried out in a well-controlled wave flume for different wave loading conditions of varying incident wave steepness and wave impact conditions. The evolution of local wave characteristics and geometric properties of breaking waves is investigated along the wave flume. The sensitivity of the vertical distribution and the variation of peak pressures to small changes in time and spatial scale is assessed during the impact. During the breaking wave interaction with a monopile, the wave impact characteristics such as pressure rise time, duration of impact, maximum pressure, and pressure impulse are analyzed. The measured geometric properties and impact characteristics are in good agreement with previous studies. The impact region and its correlation with wave characteristics and geometric properties are evaluated and discussed.