Journal ArticleDOI
Unsteady characteristics of the static stall of an airfoil subjected to freestream turbulence level up to 16
TLDR
In this paper, a local approach based on the study of the oscillation zone is proposed to obtain the length of this zone, which is found to be independent of the turbulence level.Abstract:
Fluctuation of the separation point on an airfoil under high turbulence level is investigated using pressure measurements and flow visualisations. The characteristics of the unsteady loads induced by Karman vortex shedding are studied. This is related with a local approach based on the study of the oscillation zone. A method based on the pressure standard deviation is proposed to obtain the length of this zone, which is found to be independent of the turbulence level. This result is in agreement with that obtained by spectral analysis which shows no effect of the turbulence level on the Karman vortex shedding frequency.read more
Citations
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Dissertation
Aerodynamics of wind turbines
TL;DR: In this paper, a study of rotor blade aerodynamic performances of wind turbine has been presented in which the aerodynamic effects changed by blade surface distribution as well as grid solution along the airfoil.
Journal ArticleDOI
Rotational and turbulence effects on a wind turbine blade. Investigation of the stall mechanisms
TL;DR: In this paper, a method to determine the position of the separation point on the rotating blade, based on the chordwise pressure gradient in the separated area, is proposed to evaluate rotation and turbulence effects on a wind turbine blade aerodynamics, focusing particularly on stall mechanisms.
Journal ArticleDOI
Turbulent intensity and Reynolds number effects on an airfoil at low Reynolds numbers
TL;DR: In this paper, the aerodynamics of a NACA 0012 airfoil at the chord-based Reynolds numbers (Rec) from 5.3 × 103 to 2.0 × 104 were investigated.
Journal ArticleDOI
Effect of rotor aspect ratio and solidity on a straight-bladed vertical axis wind turbine in three-dimensional analysis by the panel method
Qing'an Li,Takao Maeda,Yasunari Kamada,Kento Shimizu,Tatsuhiko Ogasawara,Alisa Nakai,Takuji Kasuya +6 more
TL;DR: In this paper, the effect of rotor aspect ratio and solidity on the power performance of straight-bladed VAWT was investigated in three-dimensional analysis by panel method based on the assumption of an incompressible and potential flow coupled with a free vortex wake.
Journal ArticleDOI
Modelling the effect of freestream turbulence on dynamic stall of wind turbine blades
Yusik Kim,Zheng-Tong Xie +1 more
TL;DR: In this paper, large-eddy simulations of flow over a pitching airfoil are conducted to study the effect of freestream turbulence on the aerodynamic characteristics of wind turbines.
References
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Book
Atmospheric Boundary Layer Flows: Their Structure and Measurement
J. C. Kaimal,John Finnigan +1 more
TL;DR: In this paper, Spectra and cospectra over flat uniform terrain, Flow over plant canopies and Flow over changing terrain are used to observe the boundary layer of a plant canopy.
Journal ArticleDOI
Experiments on the flow past a circular cylinder at very high Reynolds number
TL;DR: For R > 3.5 × 10^6, definite vortex shedding occurs, with Strouhal number 0.27 as discussed by the authors, while for R > 0.7, the vortex shedding rate becomes constant.
Journal ArticleDOI
The use of a contraction to improve the isotropy of grid-generated turbulence
TL;DR: In this article, the average kinetic energies of normal velocity components in decaying, grid-generated turbulence are equilibrated by a symmetric contraction of the wind tunnel, and this equality can persist downstream.
Journal ArticleDOI
Fluctuating lift and drag on a long cylinder of square cross-section in a smooth and in a turbulent stream
TL;DR: In this paper, the authors present the results of measurements of fluctuating lift and drag on a long square cylinder and find that the presence of large-scale turbulence in the stream had a marked influence on both the steady and the fluctuating forces.
Journal ArticleDOI
The structure of a separating turbulent boundary layer. Part 1. Mean flow and Reynolds stresses
TL;DR: In this paper, a two-dimensional, separating turbulent boundary layer for an airfoil-type flow in which the flow was accelerated and then decelerated until separation is presented.