Interplay between advective, diffusive, and active barriers in Rayleigh-Bénard flow

Recent developments in the theory of objective coherent structures have provided a wealth of approaches to identifying transport barriers in three-dimensional (3D) turbulent flows. Specifically, theoretical advances have been incorporated into numerical algorithms that extract the most influential advective, diffusive and active barriers to transport from data sets in a frame-indifferent fashion. To date, however, there has been very limited investigation into these objectively defined transport barriers in 3D unsteady flows with complicated spatiotemporal dynamics. Similarly, no systematic comparison of advective, diffusive and active barriers has been carried out in a 3D flow with both thermal and convective features. In our study, we utilize data from turbulent Rayleigh-Bénard convection simulations to uncover the interplay between advective transport barriers (Lagrangian coherent structures), material barriers to diffusive heat transport and objective Eulerian barriers to momentum transport. For a range of Rossby numbers, we visualize each type of barrier and assess their evolving physical role under changes in the relative influence of mechanical and thermal forces.