Numerical Simulation of a Wind Turbine with a Hydraulic Transmission System

This paper describes numerical modeling and analysis of wind turbines with high-pressure hydraulic transmission machinery. A dynamic model of the hydraulic system is developed and coupled with the aeroelastic code HAWC2 through external Dynamic Link Library. The hydraulic transmission system consists of a hydraulic pump, transportation pipelines, a hydraulic motor, and check valves. Using the Runge-Kutta-Fehlberg method with step size and error control, we solved the Ordinary Differential Equations of the hydraulic system in the time domain with time steps smaller than the one used in the HAWC2 main program. The numerical approach is efficient and robust. Under constant and turbulent wind conditions, the performances of a land-based turbine during normal operation are presented.