Turbulent Flow Characterization and Modeling over a Submerged Hydrophone

The potential for tidal energy extraction in high-flow environments represents an important renewable energysource around the world, and among the most important in the Bay of Fundy. In order to safely andsustainability extract this energy, proper understanding of the environment and the potential impact of tidalturbines on this environment is paramount. One of the ways to perform these types of studies is by listening tothe environments using sophisticating underwater hydrophones; the information obtained from such devicescan help determine the behaviour of marine mammals or the impact of shipping lanes for example.Ocean Sonics Ltd. is a world leader in underwater hydrophone technologies, and has identified a critical issuein the operation of such devices in high-flow environments: the increase in turbulence in the flow around thedevice results in pseudo-noise, i.e., pressure variations induced by turbulence that are perceived as noise by thedevice. This pseudo-noise interferes with the main function of the hydrophone and a solution to eliminate it, orat least reduce it, must be searched for.This research project will focus on characterizing the nature of the induced turbulence around the hydrophoneboth numerically using computational fluid dynamics (CFD) and experimentally by running tests in theDalhousie Engineering tow-tank. The result of this work will lead to a better visualization of the turbulentflow and the capacity to diminish its impact on the hydrophone by modifying its geometry.This first step in optimizing the shape of the hydrophone to counter the pseudo-noise problem will enableOcean Sonics to offer a one of a kind hydrophone for high-flow environments. This competitive advantagewill benefit both the company and the Canadian economy.