Heat transfer in a pure near-critical fluid: diffusive and convective regimes in 3He

Abstract Results are presented on the heat transport in 3 He below and above the onset of convection in a Rayleigh–Benard cell with aspect ratio of 57. The experiments were conducted along the critical isochore, where the temperature difference Δ T across the fluid layer was measured as a function of time t for various values of heat current q . The transients Δ T ( t ) upon turning the heat flow on and off are described. As q is increased, unusual damped oscillatory patterns in Δ T ( t ) are observed until a steady state is reached. These patterns evolve as the Rayleigh number increases.