An extended form of the Morison equation force model is considered for the case of an offshore structure vertical leg lement in a combined wave and current flow field. The measurement data used in the analysis is that from OTS(Ocean Test Structure) investigation in the Gulf of Mexico, with the data in the form of 27-30 second wave segments containing velocity and force component measurements in two perpendicular directions in the horizontal plane. The analysis method used was the system identification technique that has been previously applied with success to similar type data when using the conventional Morison force model, with the objective being the determination of the drag and inertia force coefficient values together with the variation of these coefficients with different characteristic flow parameters. The results support the use of the extended Morison model, but the force coefficient values do not indicate any definitive trend in terms of the current velocity parameter. The force coefficients found here are only useful as an additional contribution to a data base for establishing design ranges of such coefficients. Keywords include: Morison equation; waves; currents; wave forces; offshore structure; drag coefficient; inertia coefficient.The force coefficients found here are only useful as an additional contribution to a data base for establishing design ranges of such coefficients.
|Title||:||System Identification Analysis of Inertia and Drag Coefficients for Offshore Structure Forces Due to Combined Ocean Waves and Currents|
|Author||:||P. Kaplan, HYDROMECHANICS INC PLAINVIEW NY.|