Wave run-up on composite bucket foundation due to random waves: Model tests and prediction formulae

Abstract

Wave run-up around foundations is a hot research topic in offshore wind engineering, particularly for novel composite bucket foundations (CBFs). This study investigates wave run-up on a CBF due to random waves via physical model experiments. The variation in wave run-up around a CBF and the influence of relative wave height on the maximum relative wave run-up is analysed. The experimental results show that the maximum relative wave run-up is found at the 0° marking, and the lowest wave run-up heights occur between the 108° and 144° markings. Moreover, the velocity stagnation head theory (VSH theory) and M5ʹ model tree are employed to predict the wave run-up and obtain an optimum prediction model. Statistical indicators, including the coefficient of determination, agreement index, scatter index, and bias, were used to evaluate the performance of the generated formulae. The prediction formula developed by the VSH theory combined with the second-order Stokes wave theory based on the particle velocity at the mean free surface has good performance in the prediction of wave run-up on the CBF due to random waves. The performance of the formula for relative wave run-up was developed using the M5ʹ model tree based on the scatter parameter, relative wave height, and wave steepness and was optimal according to statistical indicators. The relative wave height plays a crucial role in wave run-up prediction. The relative wave run-up height increases with an increase in the scatter parameter, relative wave height, and decrease in wave steepness. These two methods are recommended for predicting wave run-up on CBF owing to random waves.