Internship or Graduation: Propeller Sound

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About us

At Damen, much effort is put in designing silent and comfortable ships. Therefore sound level predictions are made to judge the feasibility of each design. This of course asks for accurate prediction methods.

Aspects covered in these prediction methods are:

• The prediction of structure borne as well as airborne excitation levels of diesel engines, gearboxes, generator sets, propellers, etc.
• Predicting the dynamic response of the ship structure, such as the input mobility of the engine foundation and the transfer of vibrations through the ship structure.
• Prediction of attenuations due to acoustic countermeasures, such as resilient mountings, floating floors, visco-elastic damping, additional absorption, etc.
• Prediction of radiation of lining and absorption of the sound levels in the cabins.
• Prediction methods always needs validation by means of measurements. For this purpose, use is made of advanced measurement equipment.

Within the RD&I department, the research team Sound & Vibrations is dedicated to the development of these tools. One of the team members of this team will act as daily supervisor.

The assignment

Underwater radiated sound of ships is becoming an important topic nowadays as it is seen as potentially harmful for life in the ocean. One of the sources for the low frequency part of the underwater sound level of the ship is its propeller. A rotating ship propeller generates pressure fluctuations radiating into the water. Structures near the propeller, such as ducts or the ship hull above the propeller, affect these pressure fields as they act as acoustic shield or reflective surface. This assignment consists of developing a method to incorporate these effects into the currently existing prediction models and validate the results.

Use can be made of the following tools:

• Acoustic calculations based on the Ffowcs-Williams and Hawkings equations.
• Structural calculations using a Finite Element Method.
• CFD calculations (BEM and RANS)

Skills & Experience

This assignment is intended for a University Master student Naval Architecture / Maritime Technology / Mechanical Engineering / Applied Physics with:

• Affinity with acoustics and mechanical dynamics
• Familiarity with numerical methods (acoustic boundary element methods, finite element methods, RANS methods)
• Analytical oriented mind set
• Good programming/scripting skills in Matlab/Python
• Mastery of the English language (spoken and written)

What do we offer

As an intern at Damen, you will face several aspects in the field of sound and vibrations. It’s not only theory or practice, but the combination of theory with practice that leads to the best results.

• A pleasant, informal working atmosphere and professional guidance;
• A challenging, international environment where you have a lot of freedom and responsibilities;
• A very educational and fun internship;
• An internship fee and travel allowance.