Dynamic Response of a Cantilever Pile to Vortex Shedding in Regular Waves

This paper summarizes an experimental investigation of cantilever pile dynamics in response to wave excitation under vortex-shedding “lock-in” conditions. The study was carried out in regular waves for two conditions of wave length in relation to water depth. Pile response was measured in terms of top accelerations and bottom strains in both the in-line and transverse directions. Vortex-shedding lock-in is shown to produce substantial dynamic amplification of deflection not only in the transverse direction, but also in the in-line direction. Results indicate that the Morison equation is inadequate to describe the in-line force under vortex-shedding lock-in.