Marine hydrokinetic (MHK) devices generate electricity from the motion of tidal and ocean currents and ocean waves and provide another source of renewable energy. Additionally, MHK devices are also a new source of anthropogenic noise in the marine ecosystem and must meet regulatory guidelines that mandate a maximum amount of noise that may be generated. In the absence of measured levels from in-situ deployments, a model for predicting the propagation of sound from an array of MHK sources in a real environment needs to be established. A 3D finite-difference, time-domain solution to the governing velocity-pressure equations is used, which permits a finite number of complex sources and spatially varying sound speeds, bathymetry, and bed composition. However, deterministic solutions to these types of problems cannot capture uncertainties in the source profiles that may result from operational changes. This work presents the broadband sound pressure levels from an array of MHK sources as the amplitude and frequency from each source are allowed to vary. This Monte Carlo approach demonstrates that the idealized, deterministic solution, vastly underestimates the compounding uncertainty on the final sound field and that these small variations in the source profile cannot be ignored.
Stochasticism in Noise Generated by an Array of Marine Hydrokinetic Devices
Title: Stochasticism in Noise Generated by an Array of Marine Hydrokinetic Devices
November 01, 2016
Journal: Journal of the Acoustical Society of America
Hafla, E.; Johnson, E.; Roberts, J. (2016). Stochasticism in Noise Generated by an Array of Marine Hydrokinetic Devices. Journal of the Acoustical Society of America, 140(4), 3171.