A study of the interactions of heaving cylinders

This thesis deals with the behaviour of hydrodynamic coefficients of vertical, surface piercing, circular cylinders subjected to heave motion. Three types of experiments are investigated; i) The determination of the added mass and damping coefficients of a compound cylinder in heave motion. This test is a repeat of a previously performed experiment but the accuracy of the results are improved. ii) The side forces induced on a simple cylinder due to a nearby, geometrically similar cylinder subjected to sinusoidal heave motion are determined and show good results with the numerical model. iii) The determination of the induced heave added mass and damping coefficients also due to a nearby, geometrically similar cylinder subjected to sinusoidal heave motion. These results show a reasonable amount of agreement with the predicted values. In each experiment, the effect of varying the displacement, amplitude and the frequency of oscillation are investigated. In cases ii) and iii), the cylinder separation was varied and the experiments were performed in a deep water as well as a shallow water scenario. The results of each experiment are compared to the theoretical predictions of the Matching Technique. The Matching Technique uses continuity of pressures and velocities between adjacent regions in the flow field to solve for the velocity potentials and hence the hydrodynamic coefficients.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat