Important parameters For wind turbines tip speed ratio is defined
In terms of effective angle of attack at θ = 0°, the blade chord makes zero angle of attack with the relative velocity. Since symmetrical airfoils are employed, they Rilpivirine result in no lift force at zero α. Thus, no component of force contributes in the tangential direction which causes the torque to be zero at this point. With the increase of azimuth angle, α also increases. This rise in α causes the lift force to increase due to which the magnitude of the torque becomes more positive. Near θ = 90°, the airfoil makes critical α, thus a peak in torque value is observed. Once the peak torque is reached, the blade enter stall and loses lift resulting in low torque values. As the airfoil reaches θ = 180°, again the torque goes back to zero as there is no effective α. During the path from θ = 180° to θ = 360°, α again increases to its critical value. But flow disturbance due to large vortices in the downwind path and the fact that the energy was already extracted in the upwind path, the blades contributes small towards the positive torque values.