Modeling Coastal Virginia Offshore Wind bubble curtain effectiveness

The Coastal Virginia Offshore Wind (CVOW) consists of two turbines roughly 40 km off the coast of Virginia Beach, Virginia. Water- and seabed-borne acoustic signals from impact pile driving at CVOW were recorded during the installation of these turbines in May 2020. In-water pressure signals were measured using various methods at multiple ranges. The water depth at the wind turbines and the measurement locations were about 26 m. During installation, one of the piles utilized a double bubble curtain during construction, while the other did not. Bubble curtains are used to reduce the acoustic impacts of pile driving by creating a barrier of bubbles around the source. This arrangement has allowed for an in-depth analysis of the bubble curtain's noise control characteristics. Analysis of acoustic measurements found that bubble curtains are effective at frequencies above 200 Hz and can reduce the Sound Power Level by more than 25 decibels at certain frequencies and depths. CVOW monopile installation was modeled using a coupled Finite Element and Parabolic Equation model to replicate the insertion loss of the bubble curtain. The modeled and measured insertion loss were compared. Frequency analysis of seabed-borne propagation was also performed to contrast water-borne propagation. [Work sponsored by BOEM.]