Flow Visualization and PIV Measurement of Flow Field around a Darrieus Rotor in Dynamic Stall

Article type: Research Article

Authors: Fujisawa, N. | Takeuchi, M.

Affiliations: Department of Mechanical and Production Engineering, Niigata University, 8050 Ikarashi 2, Niigata, 950-2181, Japan | Department of Mechanical System Engineering, Gunma University, 1-5-1 Tenjin, Kiryu, 376-8515, Japan

Abstract: The flow field around a Darrieus rotor in dynamic stall is studied by flow visualization and PIV measurements. The visualization is carried out by dye injection technique while the phase averaged velocity distributions around the blade are measured by PIV combined with a conditional imaging technique. The results indicate the appearance of dynamic stall phenomenon due to the shedding of two pairs of vortices from the blade during one rotation of the rotor. These stall vortices are produced by the separation of flow over the inner surface of the blade and the formation of roll-up vortices from the outer surface. The second stall vortices develop along the blade and strongly interact with the flow field near the blade, affecting the aerodynamic performance of the rotor.

Keywords: flow measurement, flow visualization, PIV, wind turbine, dynamic stall, fluid machinery

Journal: Journal of Visualization, vol. 1, no. 4, pp. 379-386, 1998