EVALUATION OF SHIP RADIATED NOISE-LEVEL FROM NEAR-FIELD MEASUREMENTS

Recently it has become necessary to determine far-field characteristic s of marine vehicle noise from near-field measurements. It is possible to compute far-field characteristics from near-field measurements by using the Helmholtz integral equation. But this method is not practica l because a great number of points are required to obtain them. This p aper presents a simple equation to obtain the source levels of marine vehicles, which is used to evaluate far-field characteristics from nea r-field data. Good agreement with experimental results from ships is o btained.