We prove a new upper bound on the vertical heat transport in Rayleigh–Bénard convection of the form
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pan> under the assumption that the ratio of Prandtl number over Rayleigh number satisfies
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pan> where the non-dimensional constant
c0 depends on the aspect ratio of the domain only. This new rigorous bound agrees with the (optimal)
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pan> bound (modulo logarithmic correction) on vertical heat transport for the infinite Prandtl number model for convection due to Constantin and Doering [P. Constantin, C.R. Doering, Infinite Prandtl number convection, J. Stat. Phys. 94 (1) (1999) 159–172] and Doering, Otto and Reznikoff [C.R. Doering, F. Otto, M.G. Reznikoff, Bounds on vertical heat transport for infinite Prandtl number Rayleigh–Bénard convection, J. Fluid Mech. 560 (2006) 229–241]. It also improves a uniform (in Prandtl number)
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pan> bound for the Nusselt number [P. Constantin, C.R. Doering, Heat transfer in convective turbulence, Nonlinearity 9 (1996) 1049–1060] in the case of large Prandtl number.