Predicting the Hydrodynamic Acoustic Signature of CFAV Quest in the Near Surface Environment

Abstract

Three models for the generation and propagation of hydrodynamic noise near the ocean surface are presented, and are compared for their ability to predict hull noise generated by CFAV Quest. The simulated fluctuating pressure field on the hull is also validated against experimental results. The near field flow is first solved using the NWT CFD package, and the hydrodynamic noise is calculated using the Lighthill-Curle acoustic analogy. The far field sound is obtained using three methods: a method of images solution to the Lighthill-Curle equations, a simple source model of the transmission loss, or a normal mode model of the transmission loss. Both the simple source and method of images models improve the SPL predictions of the Lighthil-Curle equations. Best performance is obtained from the method of images, improving predictions by approximately 40 dB. The normal mode model is shown to give poor results, due to assumed sea-floor boundary conditions.