Flow-induced sound and vibrations with applications to pipeline safety and mitigation of ocean noise pollution

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Flow-induced vibrations and noise (FIVN) are important issues in a variety of engineering systems involving both internal and external flows. For example, they can lead to vibrations and fatigue failure of pipelines that are used for transporting fluids. Also, acoustic noise pollution from marine vessels is emerging as a major concern for the marine industry, certification organizations and the general public due to the intensified commercial shipping activity and increased public awareness of its impact on the environment. Accurate prediction of the FIVN presents a formidable challenge in the presence of multiphase flows. In particular, the cavitation phenomenon, i.e. formation of vapor bubbles in a liquid flow leads to extremely high levels of radiated noise. Cavitation commonly occurs in control valves in pipelines and during off-design operation of marine propellers. The proposed program will address the key issue of increasing fidelity of the cavitation noise models while minimizing the associated computational costs. Our research group will investigate the fundamental mechanisms of sound generation using a combined experimental and computational approach, complemented by theoretical modeling. Multiphase fluid flow will be simulated by solving the unsteady Reynolds-averaged Navier-Stokes equations. Formation of liquid droplets or gas bubbles will be modeled by solving an equation for the probability distribution function for the corresponding phase. In addition, a large eddy simulation (LES) approach will be employed in selected cases. Particle image velocimetry (PIV) will be used to measure velocity fields in physical experiments. The results, in conjunction with acoustic pressure measurements, will provide insight into the structure of the acoustic sources. I have extensive experience in the field of acoustically-coupled flows. Moreover, our collaborations with the leaders in the field of cavitation noise measurements (University of Genoa) and environmental acoustic monitoring (JASCO Applied Sciences Ltd.) will enable significant contributions both in terms of advancing fundamental knowledge and its practical application. In addition to improving the statistical analysis platform presently employed for passive acoustic monitoring, the ability to validate the developed mathematical models using the largest database of ship noise measurements in the world (presently containing over 7000 vessels) uniquely positions our research group for making a fundamental breakthrough in the field. Training of highly-qualified personnel (HQP) in the area of FIV control and mitigation of ocean noise pollution is of strategic importance to Canada. In the course of the proposed program, I will provide training to nine graduate students, which will lead to long-term impact in this field.