My area of responsibility lies in the control flap actuator design (using Shape Memory Alloys); other people are looking at the effects of fatigue reduction. Additionally, the right controller has a large impact on the achieved results; this is the job of yet another person. We are a group of people who at this time are specializing in our respective area's. Last year a setup was placed in the low speed windtunnel and even with a very simple PID controller the smoothing effect was quite dramatic. There is a movie available that shows the before and after, but as all within this project it has not been cleared for publication without authorisation. Same with respect to the data we have achieved.

Basically what I'm trying to say to you here is that theoretically the effect can be quite significant as supported by initial real life tests in much simplified (windtunnel) tests, HOWEVER, there are some serious issues to be solved in the area of the flap actuators and the also the multivariable controller. When the later is not implemented correctly then the system can actually increase the loads and reduce fatigue life. In my case I need to boost as very inexpensive and simple SMA actuator to much higher speed and accuracy; this to avoid installing any expensive and complex hydraulics or pneumatic systems.

The data you are looking for is sadly not available yet with sufficient accuracy as that would require a real-life test setup comparable to the turbines being installed now. We are still some ways from that.

My reply has to suffice at this; both to limits in what we know now and agreements of confidentiallity.

I'm sorry,

Wouter