CANARY: A simple model of ambient noise and coherence

This paper describes CANARY, a ray-based model of ambient noise and noise coherence designed for hull-mounted arrays composed potentially of individually directional (or baffled) hydrophones, A brief theory and inputs are described, and it is shown that the model can produce results compatible with wave treatments such as RANDI, The model can calculate noise level, correlation function, noise directionality and array response principally for distributed noise sources such as wind, rain or groups of ships. Some localisation of these distributions is allowed for, and point source calculations are also possible. Some examples of outputs and performance under various conditions are discussed. It is shown that baffling of hydrophones can produce some surprisingly beneficial effects that need to be modelled with care. (C) 1997 Elsevier Science Ltd.