Three-dimensional structure of the thermal boundary layer in turbulent Rayleigh-Bénard convection: A Lagrangian perspective

This study is establishing a new method to characterize the thermal boundary layer in turbulent Rayleigh-B\'enard convection. Transition from the convection dominated bulk domain to the diffusion dominated boundary layer can be identified by extrema in the time-variation of the temperature along the fluid-parcel pathlines. We demonstrate that our method reveals the spatiotemporal structure of the boundary layer.