Thesis (Ph.D.) - Asian Institute of Technology, 1972

In recent years problems of wave forces on submerged structures such as oil storage tanks in coastal waters and under{u2014}water tunnels are of great interest. Experiments have been performed by many investigators to determine wave forces on submerged objects. A unique relationship among the variables could not be formulated however due to the many variables involved and inappropriate dimensionless parameters being used. In this dissertation a closed form solution describing the force and moment due to progressive and standing waves of an inviscid fluid on a horizontal circular structure are determined. The analysis uses diffraction theory with the simplifying assumptions that the effects of the scattered wave on the free surface and bottom are negligible. This assumption is later checked and found to be reasonable. Solutions describing forces and moments on a 180 degree sector of a right circular cylinder resting to the bottom are also included. An IBM ll3O digital computer was used for the numerical calculations based on the theoretical solutions. Experiments were performed to check the validity of the theoretical solutions for both progressive and standing waves. PVC-pipes having outside diameters of 3.0", 3.5", 4.5" and 6.5" were used as models. Twelve ratios of water depth to diameter of model ranging from 2.5 to 7.0 were tested. Keulegan and Carpenter's experimental results describing wave forces produced by standing waves on circular cylinders were further analysed to describe the relationship between the drag force and a parameter in terms of wave period.

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctoral of Engineering