Benchmark experimental study on wave run-ups of fixed four-rounded-square-column array in regular waves

Wave run-up on surface-piercing columns is an important phenomenon in offshore engineering.Previous studies have mainly focused on a single column and circular column arrays.This study is concerned with the wave run-up ratio and the wave force on a fixed array of four rounded square columns.A series of regular wave tests were conducted,and the effects of wave periods and steepness were investigated.The nonlinearity of the wave run-up under incident waves with a small period is more sensitive to wave steepness.Utilizing empirical mode decomposition(EMD)and fast Fourier transform(FFT)methods,the measured signals were separated into three components representing characteristics of the incident wave component(IMF1),near-field interference(IMF2),and far-field low frequency reflected wave(IMF3),respectively.The proposed methods are helpful for studying the mechanism of near-field interference,and the experimental data are essential benchmarks for validating further numerical simulations of wave runups on rounded square columns.