Sonar Dome Vibration Analysis

Francesca Magionesi

There has been a recent move towards utilizing bulbous bows on ships to house different types of sonar systems, but it is not definite how much structural vibration might interfere with the functioning of a transducer array inside the sonar dome. INSEAN, the National Institute for Studies and Experiments of Naval Architecture in Italy, needed a way to simulate what is happening when the turbulent boundary layer interacts with the bulbous bow in order to determine how much self-noise this creates.

They first created a small-scale model to capture the turbulent boundary layer excitation and that gave them a full-scale fluid load expression. They then created a full-scale model within COMSOL Multiphysics, taking the complexity of the composite material used for the bulbous bow and the turbulent boundary layer load into account. LiveLink™ for Pro/ENGINEER® enabled the team to bring CAD data for the different parts of the bulbous bow into COMSOL Multiphysics.

Experimental set-up of a 1:8 scaled model of the bulbous bow. A section of the bulbous bow has been substituted with a transparent material on which accelerometers have been placed.