Combined Loading of a Wave and Surface Current on a Fixed Vertical Slender Cylinder

Abstract

A study on the loading of an oblique surface wave and a surface current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in the present paper. The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. The surface current considered in this report, is assumed uniform and acting over a layer of fluid that extends from the free surface to a specified finite depth. Prior work assumes that uniform currents existed over the total depth of the fluid domain. In this paper we extend the approach considered in Zaman and Baddour (2004) for the wave-current analysis. Morison et al equation is deployed for the load computations in all cases. The above model is utilized to compute the loads on a slender cylinder for a wave with varying range of incidence current field. Computations of the moments are also done for the case when current is existed over the whole water depth of the domain.