wind turbine aeroelasticity

JEHO BV AEROELASTIC Tools

Aeroelastic Tool WAF1C

At JEHO BV we are also actively developing software. The first tool we have developed is aimed at being used in the wind turbine aeroelasticity training that we provide. It is called WAF1C (pronounce: wafic; Work of Aerodynamic Forces in 1 cycle).

The tool calculates the aerodynamic work done in one cycle of a blade mode, where the blade mode shape in three directions as well as the phase differences between these three directions are provided as input, together with wind speed, pitch angle, blade chord and twist, aerofoil distribution, aerodynamic coefficient tables and frequency. 

purely out-of-plane), in-plane and torsion during one cycle of the mode. Several results can be evaluated: the total work done (if positive, the mode is unstable), the angles of attack along the different radial points during the cycle etc. You can try to find out what the effect is of the different phase angles: if the mode motions are all in phase they will reach maximum amplitude at the same time, if there is a 90 degree difference, the maximum of one direction will occur when in the other direction the amplitude will be zero. Phase differences are not always taken into account in aeroelastic evaluation tools, but they have very large effects on the final damping and can provide very illustrative results when trying to understand why vibrations are occurring on wind turbine blades. The phase differences are caused by the aerodynamic forces.

The tool is used during the courses, to illustrate different properties that affect aerodynamic damping, but if you are interested in obtaining a license for this tool, please feel free to contact us! You can reach us by e-mail: info “@” jeho . nl

An example obtained using the tool is shown above. This shows what is often the case, the out-of-plane motion has a lot of damping (so negative work done by the aerodynamic forces) while the in-plane motion is unstable. Of course the sum of these contributions (and torsion contribution if applicable) provides the total work done for the inputted mode shape and therefore the outcome: aerodynamic forces provide damping for this mode or result in an instability.