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Prof. Jacques Magnaudet

CNRS /IMFT (France)

TitleFrom Leonardo to StabFem: the long story of path instability of rising bubbles made short

Prof. Jacques Magnaudet
Jacques Magnaudet is a Senior Researcher at CNRS, working at IMFT in Toulouse, France. His research focuses on several aspects of hydrodynamics and turbulence in two-phase flows and inhomogeneous fluids. He has long been fascinated by the complex motion of rigid and deformable objects in fluids, be they particles, drops, bubbles or living organisms. Using or developing asymptotic models, numerical codes and simple experiments, he has contributed at a better understanding and prediction of the hydrodynamic loads acting on these bodies when they move in non-uniform or time-dependent flows, and at elucidating the entangled mechanisms leading to their path instability when their motion is gravity- or buoyancy-driven.
He is an associate editor of the Journal of Fluid Mechanics and currently serves as secretary general of EUROMECH, the European Mechanics Society.
This talk offers an opportunity to review the most significant advances achieved over the last three decades in our understanding of the path instability phenomenon affecting millimeter-sized gas bubbles rising in low- or medium-viscosity fluids. Based on predictions of fully-resolved numerical simulations and global linear stability analyses, and comparisons with reference experiments, it is shown how wake instability, dynamical coupling between the bubble and fluid through the constant-force and zero-torque constraints, and bubble deformability interplay in the genesis of this intriguing phenomenon.