Measuring the effects of wave action around piers - Using computer vision techniques as a contactless measurement system

Sediment transport processes caused by wave action in surface waters and around offshore platforms is interesting for environmentalists and engineers. However, problem arises when trying to measure erosion and scouring processes because the instrumentation should not disturb either the fluid motion or the sediments. In this study, computer vision techniques based on the use of structured light were used for three-dimensional (3-D) measurements of the flow-sediment interactions with piers. Laboratory applications were made in wave flumes and wave tanks for investigating the erosion processes around a vertical pile or for investigating small-scale bedforms formation. Analysis elucidated the time evolution and morphodynamics of the scour process, from a flat bed initial condition until equilibrium. The analysis of the evolution of the maximum scour depth showed that two different behaviors appear: a rapid primer of the scour process that reaches the equilibrium condition in 250 cycles, and a delayed primer, 200 cycles later.