Effect of Stall Delay Models on Momentum Distribution of Wind Turbine’s Blade under Yaw Condition: Compared to Mexico Experiment

In this paper, the effect of stall delay on distribution of normal forces in different sections of rotor are studied by an enhanced version of the blade element momentum theory (BEM), based on the 3D correction Chaviaropoulos and Hansen mode. This model is computed at wind speed of 24m/s under the yaw angle 15◦. It is found that the BEM calculation on the outer (the radial distance more than 35% spanwies) spanwise is more trustable than inner spanwise. At 60, 82 and 92% spans, the 3D correction does not affect the output result and stall does not occur. Relative velocity rose dramatically at 25 and 35% spans, consequently angle of attack increased too particularly between azimuth angles from 270◦ up to 90◦. In this regions, stall phenomena are happened. Also it is found that the 3D correction has the maximum effect on 35 and 25% spans.  The maximum improvement is 99.57% at 35% section and the azimuth angle 121◦.