Abstract
In renewable energy, offshore wind turbines are increasingly recognized as significant sources of underwater noise, with growing concerns about their impact on marine life. A key noise contributor is the structural vibration from the turbine's gearbox, transmitted through the tower to the water. This study re-analyzes the underwater noise of a single turbine using field measurements from the Utgrunden wind farm. Turbines are modeled as idealized Euler-Bernoulli beams with a lumped mass at the top, and the analytical response serves as a boundary condition for the employed Combined Helmholtz Integral Equation Formula (CHIEF) underwater noise simulation implementation. By matching CHIEF's output to field data using gradient descent, the approach effectively approximates the noise measurements, despite some limitations like proximity, free surface, and bottom reflection. The findings suggest that cumulative noise from the Utgrunden wind farm is detectable several kilometers away, with in- and out-of-phase noise interactions causing fluctuating noise levels near the farm. This method can optimize wind farm layouts to avoid noise peaks in sensitive areas