Dali Kong, Professor, Shanghai Astronomical Observatory, Chinese Academy of Sciences

Shipeng Mao, Professor

Topographically-induced fluid motions in a precessing cylinder with irregular sidewall

8:00-9:00 December 7 (Thursday),Z311

We investigate precessionally driven viscous flows confined in a cylindrical container that rotates rapidly about the symmetry axis and precesses about a different axis. The container is then modified by adding a barrier onto the cylindrical sidewall. We employ a finite element method to solve the dimensionless Navier-Stokes equations with precession terms defined in the modified cylindrical geometry with different barrier sizes. A three-dimensional tetrahedralization is applied, resulting in a finite element mesh that is carefully constructed with denser nodes in the vicinity of the bounding surface for resolving the thin viscous boundary layer. We find that the existence of barriers causes different degrees of change when the Poincare number increases. Under the influence of rapid precession and significant boundary topography, a standing vortex is generated at the trailing side of the barrier. Although a barrier generally cannot stop inertial wave propagation, sidewall-localized flows are substantially distorted, and rich turbulences are observed elsewhere in the internal flows.

Short Bio:Dr. Dali Kong obtained his BSc degree from the Department of Astronomy, Nanjing University, in 2008. He then spent time at the University of Exeter, UK, earning his PhD in Applied Mathematics in 2012. After that, Dr. Kong continued his research fellowship in the Centre for Geophysical and Astrophysical Fluid Dynamics, University of Exeter. In 2017, Dr. Kong started a new post as a research professor at the Shanghai Astronomical Observatory, Chinese Academy of Sciences. By Dec. 2023, Dr. Kong has authored 49 peer-reviewed publications. He was awarded the 2016 Royal Astronomical Society Winton Capital Award for his contribution to studies of gaseous planets.