One of the results of the development of wind energy conversion solutions for the built environment is the reappearance of Vertical Axis Wind Turbines (VAWTs). The application of wind turbines in urban environments presents design challenges driven by the complex wind fields experienced in the urban boundary layer. Urban Wind Turbines operate near, on and in the wake of bluff bodies larger than the rotor scale. These flow conditions might result in skewed flow operation. The objective of the current paper is to bring insight into the development of the near wake of a H-VAWT in skewed flow, namely understanding: • Blade loading asymmetry in spanwise direction. • Trajectory of the tip vortices, including inboard movement and radial expansion of the shed and trailing vorticity. • Asymmetry of the wake in spanwise direction. • Blade vortex interaction of upwind tip vortex with downwind blade passage. • Load distribution in downwind blade passage. • Effect of skew in the expansion of the mid-wake. The investigation is composed of experimental wind tunnel research of a two bladed H-Darrieus VAWT model with Particle Image Velocimetry, and modeling of the rotor and wake with a 3D unsteady panel method. Simulations of the rotor in skewed flow are validated with the experimental PIV data and with the torque measurements of 1 and 2. The results of the panel model, validated by experiments, show the impact of skew angle on the near wake's development, both for the upwind blade passage as well as the downwind blade passage.
|Title of host publication||Proceedings of the 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition, 5-8 January 2009, Orlando, Florida, USA|
|Place of Publication||Orlando, FL|
|Publication status||Published - 2009|