On the Evolution of Different Types of Green Water Events—Part II: Applicability of a Convolution Approach

Abstract

Recent research related to the evolution of different types of green water events, generated in wave flume experiments, has shown that some events, such as plunging-dam-break (PDB) and hammer-fist (HF) types, can present multiple-valued water surface elevations during formation at the bow of the structure. However, the applicability of analytical models to capture the evolution (i.e., the spatio-temporal variation of water elevations) of these events has not been tested thoroughly. This could be useful when estimating green water loads in the preliminary design stage of marine structures. The present work extends the research by Fontes et al. (On the evolution of different types of green water events, Water, 13, 1148, 2021) to examine the applicability of an analytical convolution approach to represent the variation in time of single-valued water elevations of different types of green water events generated by incident wave trains, particularly PDB and HF types. Detailed experimental measurements using high-speed video in wave flume experiments were used to verify the applicability of the model for single and consecutive green water events of type PDB and HF. The present work is a tentative attempt to compare an analytical approach for HF evolution. Results were also compared with the classic analytical dam-break approach. It was found that the convolution model allows the variation of water elevations in time to be captured better in comparison with the dam-break approach. The convolution model described the trend of water elevations well, particularly at the bow of the structure. The model captured the peak times well in single and consecutive events with multiple-valued water surfaces. Results suggest that this conservative and simplified approach could be a useful engineering tool, if improved and extended, to include the evolution of green water events in time domain simulations. This could be useful in the design stages of marine structures subject to green water events.