Session X02: Andreas Acrivos Dissertation Award in Fluid Dynamics Talk

Insights into Jupiter's dynamics from laboratory experiments

Earth-based observations and records from spacecrafts, including the ongoing Juno mission, are constantly challenging our understanding of Jupiter's dynamics. Among others, the structure and long-term evolution of zonal jets as well as the origin and longevity of large-scale vortices are still not fully understood. Interpreting jets and vortices properties in a global planetary circulation model is difficult because of the complex multiscale dynamics involved. Here, I will present rotating laboratory experiments, complemented by numerical simulations and theoretical analyses to model key aspects of Jupiter's fluid dynamics in simplified systems. I will focus in particular on the strong and deep east-west winds responsible for the banded aspect of Jupiter. We built an experimental setup where dominant barotropic zonal jets emerge spontaneously from a rapidly-rotating and mechanically-forced turbulent flow. In this setup, a topographic beta-effect arises from the curvature of the water free surface due to the fast rotation, which mimics the effect of the planet's curvature. These experiments demonstrate the essential role of Rossby waves in the emergence of the jets, but also in their non-linear saturation, since a Rossby waves resonance is responsible for a hysteresis between two regimes of zonal jets. In the strongly forced regime, the zonal flow contains a large fraction of the total kinetic energy, and we are able to reach the so-called zonostrophic regime argued to be relevant to gas giants. Ultimately, this setup will allow to investigate the coupled dynamics of deep jets and shallow vortices, evolving in an uppermost layer analog to the weather layer.