Based on Morison's Equation and linear wave theory hydrodynamic forces acting on inclined cylinder due to waves and crossing current at angle of oc. are analyzed. A method for calculating exciting forces is given. It is shown by experimental results that the proposed method is feasible and can be used for engineering practice.
Structures with slender members which consist of both vertical and inclined cylinder are often used in coastal and offshore engineering. for example pile wharf jacket platform etc. In nature, waves usually propagate with current. So far much research on wave-current forces acting on vertical cylinder in wave with following and opposing current field have been done, but the problem about wave-current forces acting on inclined cylinder has not been studied, which is interested by engineers, and there are only very few reports about it. The method proposed in this paper is feasible for calculating exciting forces acting on an inclined cylinder due to wave and crossing current at any angle. This method is based on Morison Equation and linear wave theory. It is well known that the selection of the drag force coefficient Co. inertia force coefficient CM as well as lift force coefficient CL is very important, and will be discussed in this paper. A model test of wave-current forces acting on an inclined cylinder due to regular wave with steady current has been carried out. Test results indicates that the method proposed in this paper is correct and feasible.
It is assumed that Morison's Equation is suitable for calculating wave-current force acting on an inclined cylinder. Other assumptions used in this study are:
the surface of cylinder is smooth.
in wave-current co-existing field, the hydrodynamic coefficients Co. CM and CL are constant along side the water depth.