Unsteady Aerodynamic Simulations of Floating Offshore Wind Turbines with Overset Grid Technology

摘要

The aerodynamic performance of the floating offshore wind turbine hasan extra level of complexity than that of bottom-fixed wind turbinesbecause of the motions of the supporting platform. In this paper, theunsteady aerodynamic performance of the NREL-5MW Baseline windturbine with periodical surge and pitch motions of its supportingplatform are investigated. The three-dimensional Reynolds AveragedNavier-Stokes equations are solved for the aerodynamic numericalsimulation. The naoe-FOAM-os-SJTU solver, which is based onOpenFOAM and overset grid technology and developed for ship andocean engineering problems, is employed. From the simulation, thetime series of the unsteady torque and thrust are obtained, together withthe detailed information of the wake flow field, and the pressurecoefficient distribution in different cross-section are also available toclarity the detailed flow filed information. The simulation results arecompared both with those obtained from aerodynamic simulation ofwind turbine without effects of platform motions, and with otherapproaches in previous studies. The simulation results show that thepitch motion has more significant effects on the aerodynamic forcesand moments of the rotor than the surge motion does. And the motionof the platform especially the pitch motion may bring very badinfluence on the turbine forces and wake flow, even on the powergeneration in case of very severe pitch motion.