Shipping noise disrupts the marine habitat. The International Maritime Organization has intensified its efforts recently to limit ship-borne noise. Despite on-going discussions, there are no regulations put into effect yet and this is considered to be due to the lack of fundamental knowledge on hydroacoustics. One of the goals of this study is to fill this knowledge gap and develop hydroacoustic prediction methods of ships and minimize ship noise, when possible. To do that, a remotely-controlled model container ship is constructed and the noise originating (mostly) from its propeller is measured. The two photographs below show the ship and the water station during the tests (left) and the team that conducted the experiments (right). The team amassing researchers from control engineering, aerospace engineering and marine engineering is led by Dr. Omer Kemal Kinaci from our faculty.

  

The noise originating from the ship is measured by hydrophones that are attached to the water station. Ship noise at different ship speeds and propeller rotation rates were measured during three-day-long tests. The graphs below show one of the test results. Sound pressure levels in the time domain (left) and the frequency domain (right) were obtained for each ship speed.

  

Noise reduction is also of interest in other engineering disciplines. Many devices that are used in daily life contain rotating machinery like ship propellers. The knowledge gained from ship propeller noise minimization will also enable these devices to operate with less noise.