Two autonomous data loggers were then mounted inside the turbine protection cover and programmed to record strains at different points along the blade throughout immersion (see figure below). Data were recovered when the turbine was removed from the water.
The figure below shows one example of the type of data recovered after a 6 month immersion period.
Variation in strain on the blade
Such data are very valuable and can be used both to help validate the calculations used to dimension the blade and to define future test programmes.