Evaluation of a multibody combustion engine simulation model for underwater noise calculation

Abstract

A ship consists of various noise sources that contribute to its overall radiated underwater noise. For silent ships like research vessels main engines are often the dominant source of radiated noise. However, traditional methods for the prediction of underwater noise appear to be inaccurate especially for low frequencies of up to 300 Hz. Therefore, a more accurate method for prognosis of underwater noise levels at an early stage of ship design needs to be developed. For the prognosis model account shall be taken of the system components engine, ship structure and water by simulation and measurement. For this reason, a multibody simulation model for large-bore combustion engines is developed. Its target application is the calculation of structure-borne noise in ship structures. For validation purposes, comprehensive measurements on a series of engines were carried out on the test bed. A comparison between measurement and simulation shows good correlation and indicates that the usage of the model for further studies together with ship structures is reasonable.