Aerodynamics of Horizontal-Axis Wind Turbines

Effect of shroud on the performance of horizontal axis hydrokinetic turbines

“…In practice, yaw operations are more usual than inline operations for a wind turbine (van Bussel, 1994). It is common that a wind turbine rotor operates at yaw angles as large as 30° for several minutes (Hansen and Butterfield, 1993). Similarly, a hydrokinetic turbine encounters changes in the direction of water streams that affects the performance of turbines.…”

Inboard Stall Delay due to Rotation

“…The present work aims at giving a conceptualization of the complex 3-D flow field on a rotor blade, where stall begins and how it progresses, driven by the needs to formulate a reasonably simple model that complements the 2-D airfoil characteristics used to predict rotor performance. Understanding wind turbine aerodynamics (Hansen & Butterfield, 1993) in all working states is one of the key factors in making improved predictions of their performance. The flow field associated with wind turbines is highly three-dimensional and the transition to two-dimensional outboard separated flow is yet not well understood.…”

Fatigue Loads Mitigation on Horizontal Axis Wind Turbines Using Aerodynamic Devices. A Survey

“…Tawade et al [21] noted that a progressive damage on mechanical components or blades may occur if rotor blades are subjected to these periodic stresses for a long period. The work of Hansen et al [22] noted that a rotating blade passing through spatially varying wind field is excited at the frequency of passage which results to energy shifts to higher frequencies and causes more fatigue build-up than anticipated. Nevertheless, long blades are flexible and they are likely to experience edge-wise and flap-wise deflections especially in high varying wind speed.…”