Study on equivalent fatigue damage of two in-a-line wind turbines under yaw-based optimum control

Abstract

ABSTRACT Offshore environment contains rich and high-quality wind resource with higher wind speed and lower turbulence intensity. In the offshore wind farm, the wake flows of different wind turbines will interact with each other, which will cause the energy loss and fatigue damage increase on wind turbines, namely wake effect. To alleviate the wake effect in the wind farm, several control methodologies have been proposed. The previous researchers have made a great progress on the power-augmentation effect. However, the fatigue damage from the wake control was not fully quantified in most current research. As a result, in this study, the fatigue damage of wind turbine blade from the wake control will be researched based on the coupled model of structural dynamics model and large-eddy-simulation-based CFD model. The flow field and dynamic loading for the wind turbine blades are simulated and analyzed. The equivalent fatigue damage (DEL) caused by the wake control for the upstream and downstream wind turbines has been calculated. It was found that the yaw-based wake control can cause 50% fatigue damage increase with increasing yaw angle. This research will provide guidelines for the design of both large wind turbine and wind farm.