Analysis of hydrodynamic forces on freestanding risers with buoyancy cans

Free-standing hybrid risers are vertical slender steel pipes that are commonly used in the oil and gas industry. These slender structures are subjected to complex hydrodynamic loads that results in fatigue damage. The tidal forces that develop on Freestanding Risers (FSR) with buoyancy cans (BC) because of varying outer pipe dimensions are investigated in this work. The study considered riser diameters of 0.2, 0.3, 0.5 and 0.6 meters as well as buoyancy can diameters ranging from 2, 3, 5 and 6 meters. The Morison equation was used in this study to investigate the wave hydrodynamic forces. Separate assessments of the lift force are also carried out consider a water depth (d) of 30 m. The findings reveal that the pipe diameter, wave heights and the wave periods have significant impacts on the hydrodynamic forces on the riser. © Published under licence by IOP Publishing Ltd.