scholarly journals Examination of forced unsteady separated flow fields on a rotating wind turbine blade

1993 ◽  
Author(s):  
S. Huyer
2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alvaro Gonzalez ◽  
Xabier Munduate

This work undertakes an aerodynamic analysis over the parked and the rotating NREL Phase VI wind turbine blade. The experimental sequences from NASA Ames wind tunnel selected for this study respond to the parked blade and the rotating configuration, both for the upwind, two-bladed wind turbine operating at nonyawed conditions. The objective is to bring some light into the nature of the flow field and especially the type of stall behavior observed when 2D aerofoil steady measurements are compared to the parked blade and the latter to the rotating one. From averaged pressure coefficients together with their standard deviation values, trailing and leading edge separated flow regions have been found, with the limitations of the repeatability of the flow encountered on the blade. Results for the parked blade show the progressive delay from tip to root of the trailing edge separation process, with respect to the 2D profile, and also reveal a local region of leading edge separated flow or bubble at the inner, 30% and 47% of the blade. For the rotating blade, results at inboard 30% and 47% stations show a dramatic suppression of the trailing edge separation, and the development of a leading edge separation structure connected with the extra lift.


Author(s):  
Oliver Fleig ◽  
Chuichi Arakawa

There is a strong need to investigate aerodynamic noise caused by large and fast rotating wind turbines, especially trailing edge and tip noise. This work constitutes the first part of a project which aims to simulate the broadband tip noise emitted when the wind turbine is in operation. Several aeroacoustics methods are analyzed and their suitability for a typical wind turbine blade is assessed. A stationary wind turbine blade in an incident flow with a large region of separated flow is studied. The surface pressure fluctuations are calculated using compressible Large-Eddy simulation (LES). The aerodynamic noise perceived in the far-field is predicted by simulating the propagation of the pressure perturbations using LES and Linearized Euler equations (LEE) in the near field and Kirchhoff’s integral method in the far-field. It was found that for the present wind turbine blade with a large region of separated flow and thus relatively large fluctuations, LES with a fine enough mesh and a third-order upwind scheme is able to compute the propagation of acoustic waves as accurately as LEE with higher order schemes and separate treatment of acoustic perturbations. The method described in this paper will be used in the future to analyze a full wind turbine blade with the aim of optimizing the tip shape for reduced noise emission.


Author(s):  
Gwochung Tsai ◽  
Yita Wang ◽  
Yuhchung Hu ◽  
Jaching Jiang

Author(s):  
Aldemir Ap Cavalini Jr ◽  
João Marcelo Vedovoto ◽  
Renata Rocha

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