Transverse Oscillations of a Vertical Pile in Waves Available to Purchase

A cantilevered pile, flexible only in the transverse direction, has been submitted to wave action. It has been found that resonance transverse vibrations, with natural frequency f_n, are induced by eddies shedding in waves having frequency f_w = 1, 1/2, 1/3, 1/4 f_n. A lock-in effect has been observed within the range of 0.9 f_n ≤ f_w ≤ 1.1 f_n. Results of a simple mathematical model find reasonable support in the experiments.