A higher-order boundary element method (HOBEM) is developed to study wave diffraction and radiation around the Truss Spar in time domain and three dimensions. In the numerical scheme adopted, a boundary integral equation method based on Green's second theorem is used to calculate the velocity potential of the resulting flow field at each time step, and the first-order free surface boundary conditions of the corresponding initial-boundary value problem are treated by a time-integration scheme to obtain the development of the flow. Additionally, catenary's theory is used to simulate the mooring system. The special case of regular wave is considered to illustrate and examine the present method, and all calculation results show the present approach is feasible in simulating the wave action on Truss Spar.
The requirement of oil and gas increases fleetly with the rapid development of industrial and civil utilization in the world. Recently the offshore petrol industry strengthens expansion towards the deep and ultra-deep water field as well as more and more deepwater drilling and production units are demanded. It is well known that, the bottom fixed units is not suitable for deepwater and should be replaced by floating units. After several decades of development, the Spar platform, as one type of floating platforms, has become one of the most attractive development concepts in the offshore industry. Since Glaneille et al (1991) gave the details about design, construction and installation of a Spar platform, Mekha et al (1995) and Ran & Kim (1996) did the research on the physical model test. Cao & Zhang (1997), Ran & Kim (1996) and Chitrapu et al (1998) calculated the Spar platform and the mooring system using different wave model and computational programs. Since the first Classic Spar platform installation in 1996, Spar platform technology has evolved from the first generation Classic Spar design to the second-generation Truss Spar design. In 2001, The first two Truss Spars have been installed in the Gulf of Mexico.
