Numerical investigation of multidirectional random wave interaction with a large cylinder

To investigate the multidirectional wave run-up and forces on a large cylinder, a numerical model of multidirectional random wave loads on a large-scale cylinder is established based on the linear theory of wave interaction with a large-scale bottom-mounted vertical cylinder. The incident directional wave is specified using a discrete form of the Mitsuyasu-type spreading function. A wave basin experiment was carried out, and the numerical calculation results were verified by the results of the physical experiment. The results indicate that the wave directionality has significant effects on the distribution of the wave run-up around the cylinder. The transverse wave force occurs due to which the multidirectional waves at the two sides of the cylinder are totally different from each other at any time because of the wave directionality. Specially, for the multidirectional random wave with small directional spreading parameter (s=5), the transverse force F-y is about 57% of the normal force F-x and cannot be neglected any more. Results can provide reference for the real engineering design.