Gao, H; Metcalfe, G; Jung, T; Behringer, RP, *HEAT-FLOW EXPERIMENTS IN LIQUID **4He WITH A VARIABLE CYLINDRICAL GEOMETRY.*,
Journal of Fluid Mechanics, vol. 174
(1987),
pp. 209-231 .
**Abstract:**

*This paper first describes an apparatus for measuring the Nusselt number N versus the Rayleigh number R of convecting normal liquid **4He layers. The most important feature of the apparatus is its ability to provide layers of different heights d, and hence different aspect ratios GAMMA . The horizontal cross-section of each layer is circular, and GAMMA is defined by GAMMA equals D/2d where D is the diameter of the layer. Results are reported for 2. 4 less than equivalent to GAMMA less than equivalent to 16 and for Prandtl numbers Pr spanning 0. 5. and 0. 9. These results are presented in terms of the slope N//1 equals R//cdN/dR evaluated just above the onset of convection at R//c. Study results are discussed.*