Experimental study on short-term statistical distributions and local spatial variability of deep-water short-crested irregular waves

Based on physical experiments of deep-water short-crested irregular waves, this study investigates the effects of wave parameters on short-term statistical distributions and local spatial variability. A target wave field was generated using a JONSWAP spectrum and a cosine-type directional spreading function, and a gauge array was arranged in a local spatial region of the wave basin to record free surface elevation time series. The effects of peak period, significant wave height, and directional spreading parameter on the exceedance probabilities of wave height and crest elevation were analyzed, and the experimental results were compared with the Rayleigh and Forristall distributions. To quantify the spatial variability of statistical results among gauges, a broadening index of exceedance probability curves was introduced. The local spatial distributions of skewness and kurtosis were also examined to characterize non-Gaussian features. The results show that the short-term statistical distributions and local spatial variability exhibit different responses under different wave parameter conditions, and the differences among gauge results become more pronounced in the low exceedance probability region. These findings indicate that local spatial variability, even within a sub-wavelength region relative to the peak wavelength​, should not be neglected in short-term statistical analyses of deep-water short-crested waves.