Ester Simoons

 
Wind energy is becoming increasingly popular as an alternative for conventional power. Impressive growth numbers have been established in Europe for quite some years and wind energy is also growing in other parts of the world.

A windmill in sea generates scour around its foundation. This scour can cause problems by changing the resonance frequency of the pile. Resonance can be a cause of metal fatigue and can therefore reduce the lifetime of a windmill. In order to prevent scour directly near the pile of the windmill, scour protection is installed. However, just outside the scour protection edge scour develops. This can cause damage to the electricity cables buried in the bed.
Edge scour is not very well understood and therefore difficult to quantify.
Delft3D will be used to compute the edge scour development and the dependency of the bed level changes on spatial variation in water depths, currents and waves. The performance of the model will be investigated by comparison with field observations from Offshore windpark Egmond aan Zee.

The aim of this research is to predict the depth, extent, location and rate of edge scour around an offshore windmill. This may result in an engineering design rule for edge scour around scour protections of offshore windmills. With this design rule the optimal location and burial depth of electricity cables can be determined. This might be a step forward for offshore wind energy to become a cost-effective scource of renewable energy in the future.

Average edge scour in Offshore Windpark Egmond aan Zee