Measurements of heat transport, as expressed by the Nusselt number Nu, are reported for turbulent Rayleigh-Bénard convection of water containing up to 120 ppm by weight of poly-[ethylene oxide] with a molecular weight of $4\times {10}^6\mathrm{g}/\mathrm{mole}$. Over the Rayleigh number range $5\times {10}^9\lesssim \mathrm{Ra}\lesssim 7\times {10}^{10}$ Nu is smaller than it is for pure water by up to 10%.

• Received 15 October 2009

DOI:https://doi.org/10.1103/PhysRevLett.104.034503