ToRoCo: 3D reconstruction of coherent flow structures in laboratory rotating convection with topography

The Earth’s magnetic field shields life and electronics from harmful solar and cosmic radiation. Magnetic fields in rocky planets are generated by convective flows of molten iron in their cores, but new evidence suggests Earth lacked a solid inner core for most of its history and thus lacked compositional convection. As a result, scientists are exploring alternative drivers, such as chemical and topographic effects at the core-mantle boundary (CMB). We conduct rotating convection experiments to study how boundary topography and rotation influence fluid flow and heat transfer.

This talk will describe the design, construction, and capabilities of our apparatus. We measure temperature, heat fluxes, and velocities to calculate the relevant Prandtl number Pr, Rayleigh number Ra, and Ekman number Ek. With water () in a cylindrical vessel (20 cm height and diameter), we reach parameter ranges of and for input heating power of 5-1000 W and rotation rates of 1-60 rpm. An octagonal shield jacket ensures isothermal lateral boundary conditions by matching the sidewall temperature to the fluid’s mean, preventing radial heat leakage. In water experiments, topography of height ~0.1 cm matches the thermal boundary layers. Multiple cameras will track tracer particles matching fluid velocity. Our experiments probe how topography interacts with wall modes, Rossby waves, initial wave modes, plumes, and Taylor columns.