Abstract
The goal of this research project is the measurement of the operational underwater sound emission of different types of 5 MW offshore wind energy converters (OWEC) under varying boundary conditions. The background of the project is the question of the exposure of marine animals to noise, especially marine mammals, in the vicinity of offshore wind farms.
The noise production of OWEC and the underwater sound propagation are influenced more or less by many parameters (boundary conditions), such as wind velocity, wind direction, sea state, water height, water flow profiles, water temperature, water temperature profiles, salinity, etc. The following problems will be investigated:
- Measurement of the underwater noise production of different types of OWEC under various boundary conditions
- Determination of the transfer function between tower vibration (structure-borne sound) and emitted underwater noise for different types of OWEC
- Influence of different boundary conditions on sound propagation
- Measurement of the total underwater noise immission of the alpha ventus wind farm at all possible boundary conditions.
To this end a total of 5 hydrophones will be positioned about 3 meters above the sea bed near 2 OWEC and near the research platform FINO1, which is located at a distance of 400 m from the wind farm. In addition acceleration sensors will be mounted at the underwater and over-water sections of the OWEC towers. Measuring computers that are installed in both OWEC and on FINO1 will digitize the signals of the acceleration sensors and hydrophones and will transmit the data to a file server onshore. The measuring system can be remote controlled from onshore so that measurements can be performed in all weather conditions.