Measuring the effects of wave action around piers

The erosion process caused by fluid action in rivers, in near-shore regions, and around offshore platforms is interesting for both environmentalists and engineers. Many studies have been made of this phenomenon. However, sediment transport processes are still far from being clearly understood. Field and laboratory investigations are extremely important for improving our knowledge of the basic forces that control such phenomena. Many difficulties arise when trying to measure erosion or scouring processes. One of the most important features of the measurement system is that the instrumentation should not disturb either the fluid motion or the sediments. Therefore, the scour due to the wave motion around a vertical pile is investigated because of the equilibrium conditions of the erosion process. Techniques for structured light and image acquisition can measure and recover sand bed evolutions. These techniques are noninvasive and provide visual reference points or lines on the bottom during morpho-dynamic evolution. This study used computer vision techniques, based on the use of structured light, for three-dimensional (3D) measurements of the flow-sediment interactions with piers. Extensive laboratory applications have been made in wave flumes and wave tanks for investigating the erosion processes around a vertical pile or for investigating small-scale bedforms formation. These methods can detect changes of the sandy bottom, such as small bed-forms or scours, with great accuracy without interfering with the measured system. They also can observe the dynamic behavior of these morphological features.