Ocean Wave Forces on Circular Cylindrical Piles

The average value of the coefficient of mass was 2.5 with a normal Gaussian distribution about this average value. Within the limits of accuracy of the tests, and within the range of conditions, there appeared to be no relationship between the coefficient of mass and the flow conditions as represented by the Reynolds number, with water-particle acceleration, or with wave period. Large lateral vibrations of the 2-ft pile were noted under the action of high waves, probably due to the alternate breaking off of the large vortices, which were noticeable. The period of these vibrations was approximately 2.5 sec and the wave period was approximately 13 sec. As a result of the effect of the vibration force, combined with the effect of the continual alternating forces due to the drag force and the inertia force, the 6-in. central supporting pile broke in the middle seat of the threads at a point 3 ft below the bottom collar. An examination of the break indicated that it was a fatigue failure.