3D wake dynamics of the VAWT: Experimental and numerical investigation

3D wake dynamics of the VAWT: Experimental and numerical investigation

Ferreira, C.
Hofemann, C.
Dixon, K.
Van Kuik, G.A.M.
Van Bussel, G.J.W.

Aerospace Engineering

Aerodynamics, Wind Energy & Propulsion

2010-01-04

The Vertical Axis Wind Turbine, in its 2D form, is characterized by a complex unsteady aerodynamic flow, including dynamic stall and blade vortex interaction. Adding to this complexity, the 3D flow causes spanwise effects and the presence of trailing vorticity and tip vortices. The objective of the current paper is to bring insight into the 3D development of the near wake of a H-VAWT, understanding: • The spanwise blade load distribution in the upwind and the downwind blade passages. • The trajectory of tip vortices, including the inboard movement and the radial expansion of the shed and the trailing vorticity. • The impact of the 3D flow phenomena on the efficiency of the VAWT. • The blade vortex interaction of the upwind tip vortex with the downwind blade passage. • The induction due to trailing vorticity. The investigation is composed of experimental wind tunnel research with Stereo-PIV and modeling of the rotor and wake with a 3D unsteady panel method. A two bladed H-Darrieus VAWT model is tested in the low speed/low turbulence wind tunnel at Delft University of Technology. Stereo-PIV measurements are used to visualize the flow in the near wake focusing on the flow field around four tip geometries. The measurement planes cover several sections of the rotor volume, allowing for the reconstruction of the evolution of the tip vortex. The formation, the convection and the dissipation for each tip vortex are quantified. The experimental PIV data is used to validate the 3D, unsteady, multi-body, free-wake panel method. The combination of the results of the panel model validated by experiments, in particular the Stereo PIV results, allows to understand the impact of the near wake development on the upwind blade passage, as well as the energy conversion process during the downwind blade passage.

http://resolver.tudelft.nl/uuid:9c8890f9-f52f-49b4-b63a-a1da87343871

https://doi.org/10.2514/6.2010-643

American Institute of Aeronautics and Astronautics (AIAA)

978-1-60086-959-4

48th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, Orlando, USA, 4-7 January 2010; AIAA 2010-643

Institutional Repository

conference paper

© 2010 The Author(s)