I have witnessed that higher values of TI lead to a decay in the Ct curves in the moderate range of wind speed (8-13 m/s). For high wind speeds it is seen that the changing TI does not have an impact on the curves but it does for moderate wind speeds. I've been trying to find a response for that, but it is not clear at all.
By definition turbulence intensity (TI) is function of mean wind speed and standard deviation of turbulence wind speed measured at specific height. TI generally reduces with increase in height above ground. but thrust coefficient (CT) for a horizontal axis wind turbine varies inversely with square of wind speed.
For low to moderate wind speeds the turbulence intensity is high, and when the turbine is in power production mode with increasing power, the controller tries to optimize the power generated by turbine to reduce the axial thrust force acting on rotor blades with an aim to increase the fatigue life of turbine/components. This causes the decay in thrust coefficient, however for higher wind speeds, the controller regulates power output to constant value by pitching blades out of wind. So, effectively TI has little or no impact on thrust coefficient curves of turbine for high wind speeds.
- Badges
- Science topic