Design of an Articulated Spar Buoy.
RHODE ISLAND UNIV KINGSTON DEPT OF OCEAN ENGINEERING
Pagination or Media Count:
A generalized analytical model of the wind, current, and wave forces on an elliptical cylinder is presented with specific application to predicting the list angle of an articulated spar buoy. The major physical and environmental parameters present in the system are then analyzed to determine their relative influence on these forces and moments. Data to validate this analytical model was obtained from both laboratory and field experiments. Model tests performed in a circulating water channel revealed that directional stability was a significant factor in determining the overall performance of elliptically cross-sectioned spars. Of the shapes investigated, only a circular cylinder with splitter plate was found to be stable and to return to an equilibrium position if displaced. Laboratory measurements of the circular cylinder list angle for various current velocities showed generally agreement with that predicted by the analytical model. Using a nominal 6 inch 16.83 cm diameter, instrumented aluminum spar 18 feet 5.49 m in length with a splitter plate, field test data was obtained over a broad range of current and water depth conditions. Data from this field experiment also showed good agreement with that predicted by the analytical model. On the basis of these results, it was concluded that for spars of circular cross-section, the analytical model is a good predictor of an articulated spars behavior and, consequently, a useful design aid. Possible improvements to both the laboratory and field tests are suggested. Author
- Physical and Dynamic Oceanography
- Marine Engineering