Jetties or drilling platforms usually stand in the water on piles. Flowing water exerts forces on the part of the piles that is located under water, possibly causing vibrations. The vibrations can lead to component failure.
The vibrations are caused by the interaction between the water and the pile. For example, flow around a pile can lead to the formation of a Karman vortex street. The detachment of these vortices causes a change in the flow direction. In the worst case the vortex shedding frequency corresponds to the natural frequency of the pile.
HM 162.61 enables the observation of a single vibrating pile. Furthermore, there are two parallel piles that stand transverse to the direction of flow, and which are made to vibrate by the flow. The distance between the piles can be varied. If the distance is too small, there will be coupled vibrations between the two piles.