Experimental techniques for turbulent Taylor–Couette flow and Rayleigh–Bénard convection

Taylor–Couette (TC) flow and Rayleigh–B´enard (RB) convection are two systems in hydrodynamics, which have been widely used to investigate the primary instabilities, pattern formation, and transitions from laminar to turbulent flow. These two systems are known to have an elegant mathematical similarity. Both TC and RB flows are closed systems, i.e. the total energy dissipation rate exactly follows from the global energy balances. From an experimental point of view, the inherent simple geometry and symmetry in these two systems permits the construction of high precision experimental setups. These systems allowfor quantitative measurements of many different variables, and provide a rich source of data to test theories and numerical simulations. We review the various experimental techniques in these two systems in fully developed turbulent states.