3D acoustic propagation modeling of the construction of the Block Island Wind Farm

The Block Island Wind Farm (BIWF) consists of five turbines in water depths of approximately 30m. The substructure for the BIWF turbines consists of jacket type construction with piles driven to the bottom pinning the structure to the seabed. These jacket legs and foundation piles were driven at a rake angle of approximately 13° from the vertical. This introduced three-dimensional sound propagation effects as indicated by measurements using a towed array during construction which showed azimuthal variability. In order to model the complicated source, we will use finite element techniques (developed by Sandia National Laboratories) to provide the starting field for a 3D parabolic equation model. Eventually the model predictions will be compared to the actual measurements taken during wind turbine construction. This finite element model will be initially validated by modeling the wave propagation in an instrumented sandbox at the University of Rhode Island (URI) before applying the model to the Block Island modeling scenario. [Work supported by Bureau of Ocean Energy Management (BOEM).]