THE EFFECT OF TURBULENT FLOW ON WIND TURBINE LOADING AND PERFORMANCE

Abstract

Wind turbines are widely used for electricity generation. Typically turbines aredeployed in farms located either on-shore or off-shore. In these arrangementsthe flow onto a turbine may be turbulent due to the disruption caused by turbineslocated further upwind. At onshore locations, turbines are typically smallerbut will often be located downwind of structures or terrain which will causethe incident flow to be turbulent. Although wind turbines have been employedcommercially for several decades, design tools are based on assumptions of quasi-steadyflow and the effect of turbulence on turbine performance is not fully understood.In this study the effects of turbulent flow on wind turbine loadingand performance were investigated by means of some sophisticated experimentalmethods in conjunction with numerical predictions. With this intention, theatmospheric boundary layer was simulated using conventional methods withinthe wind tunnel in the University of Manchester. The characteristics of the flowwere established using cross hot-wire anemometry. The maximum thickness forthe simulated atmospheric boundary layer that was produced by an arrangementof a combination of vortex generators, a barrier wall and a group of cubeswas found to be over 0.7m. This combination sustained the turbulence intensityto between 3% and 23% and the turbulence length scale between 150mmand 210mm for the downstream flow. Meanwhile, the grid turbulence generatorproduced a turbulent flow at a cross section a distance of five mesh sizes downstream,with 16% turbulent intensity and with 35mm turbulent length scale acrossthe entire cross section. These flow fields were experienced by a designed 2-Dfoil (chord=60mm,span=400mm,40000

Date of Award	1 Aug 2012
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Konstantinos Kontis (Supervisor) & Peter Stansby (Supervisor)