TITLE:
Validation of Chaviaro Poulos and Hansen Stall Delay Model in the Case of Horizontal Axis Wind Turbine Operating in Yaw Conditions
AUTHORS:
Abdelfattah Bouatem, Ahmed Al Mers
KEYWORDS:
Wind Turbine; Wake; Yaw; Stall; Stall Delay; Skewed Wake; Renewable Energy
JOURNAL NAME:
Energy and Power Engineering,
Vol.5 No.1,
January
4,
2013
ABSTRACT: Operating
in natural wind field, the horizontal axis wind turbines are subject to cyclical
variation of aerodynamic loads. This cyclical loads fluctuation is a result of two
aerodynamic phenomenon: the first one is the advancing and retreating blade effect;
the second one is related to the cyclical variation of induced velocity at the rotor
plane. In these operating conditions, the correct prediction of this load variation
is necessary to predict some important parameters linked to the fatigue and stability
of free yawing turbines. The main objective of the present study is the evaluation of the azimuthal
variation of normal force at different radial positions. To model the problem, the
blade element momentum
theory is used and wind turbine is supposed operate in yaw conditions. The aerodynamic
coefficients are corrected using Chaviaropoulos and Hansen model to take into account
the phenomenon of stall delay. A computer code was developed to obtain the numerical
values and results are compared with measurements performed in the NASA Ames wind
tunnel.