Field and Laboratory Measurement of Wave Impacts

An extensive programme of ongoing field, laboratory and numerical investigations into the characteristics of wave impacts is described and early results presented. Shock pressures are found to be highly localised, both spatially and temporally, able to propagate into cracks and, in freshwater at least, capable of reaching surprising intensities. Conventional scaling of 1:4 hydraulic model data implies that ocean waves ∼4m high could generate heads in excess of 1000m. Attention is drawn to the possibility that, in practice, such extreme pressures may be constrained by the acoustic (water hammer) limit. The parameter map used for predicting impacts is shown not to be entirely reliable and preliminary results of the numerical models are discussed.