Vendredi 19 septembre 2025 à 11h00, salle des séminaires IRPHE
Abstract: Bayesian optimisation with Gaussian process regression is applied to optimise the shape of an elastically mounted cylinder undergoing transverse flow-induced vibration (FIV). The vibration amplitude and mean power coefficient are obtained from two-dimensional numerical simulations, with Reynolds number 𝑅𝑒 = 100. First, shape optimisation is performed to maximise the amplitude of undamped vibrations. The optimised shape is found to be a thin crescent cylinder aligned perpendicular to the oncoming flow. The optimised shapes were found to exhibit a combined VIV-galloping response, which is not observed for circular and elliptical cylinders at the same Reynolds number. Shape optimisation was also performed to maximise the power coefficient, where the power generation device is modelled as a linear damper. The power-optimised cylinders were also thin crescents, but with greater curvature compared to the amplitude-optimised cylinders. Compared to the circular cylinder, improvements in the power coefficient and efficiency of up to 523% and 245%, respectively, were obtained.
Short Bio: Mark Thompson obtained a PhD in Applied Mathematics from Monash University in Melbourne Australia. After a ten year period at CSIRO (the Australian equivalent of CNRS) in Melbourne working mainly on practical industrial problems concerning mineral processing and mining, he moved to back to Monash University to work in more fundamental fluid mechanics areas. He is currently a Professor of Fluid Mechanics there. His interests include Flow-Induced Vibration, Direct Numerical Simulation and Large Eddy Simulation, Vorticity Dynamics, Flow Stability and Transition to Turbulence and Bluff Body Flows. He has been an Associate Editor of the Journal of Fluid and Structures, and is a significant contributing author to the Journal of Fluid Mechanics on many of these topics. He is a regular visitor to IRPHE.