Effect of a polymer additive on heat transport in turbulent Rayleigh-Bénard convection.
نویسندگان
چکیده
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 4x10{6} g/mole. Over the Rayleigh number range 5x10{9} less than or approximately Ra less than or approximately 7x10{10} Nu is smaller than it is for pure water by up to 10%.
منابع مشابه
Effect of sidewall conductance on heat-transport measurements for turbulent Rayleigh-Bénard convection.
For measurements of turbulent heat transport in Rayleigh-Bénard convection the correction for the sidewall conductance is usually neglected or based on measurements or estimates for the empty cell. It is argued that the lateral thermal coupling between the fluid and the wall can invalidate these approaches, and that corrections based on calculations of the two-dimensional temperature fields are...
متن کاملTransitions between turbulent states in rotating Rayleigh-Bénard convection.
Weakly rotating turbulent Rayleigh-Bénard convection was studied experimentally and numerically. With increasing rotation and large enough Rayleigh number a supercritical bifurcation from a turbulent state with nearly rotation-independent heat transport to another with enhanced heat transfer is observed at a critical inverse Rossby number 1/Roc approximately 0.4. The strength of the large-scale...
متن کاملThermal evidence for Taylor columns in turbulent rotating Rayleigh-Bénard convection.
We investigate flow structures in rotating Rayleigh-Bénard convection experiments in water using thermal measurements. We focus on correlations between time series measurements of temperature in the top and bottom boundaries. Distinct anticorrelations are observed for rapidly rotating convection, which are argued to attest to heat transport by convective Taylor columns. In support of this argum...
متن کاملPrandtl-, Rayleigh-, and Rossby-number dependence of heat transport in turbulent rotating Rayleigh-Bénard convection.
Experimental and numerical data for the heat transfer as a function of the Rayleigh, Prandtl, and Rossby numbers in turbulent rotating Rayleigh-Bénard convection are presented. For relatively small Ra approximately 10(8) and large Pr modest rotation can enhance the heat transfer by up to 30%. At larger Ra there is less heat-transfer enhancement, and at small Pr less, similar 0.7 there is no hea...
متن کاملHeat transport in turbulent Rayleigh - Bénard convection for Pr ≃ 0 . 8 and Ra ≲ 1015
We report experimental results for the heat transport, as expressed by the Nusselt number Nu, by turbulent Rayleigh-Bénard convection in a cylindrical sample of aspect ratio Γ ≡ D/L = 0.50 (D = 1.12 m is the diameter and L = 2.24 m the height). The measurements are for the Rayleigh-number range 10 <∼ Ra <∼ 10 15 and for a Prandtl number Pr ' 0.86. At these large Ra the results were exceptionall...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Physical review letters
دوره 104 3 شماره
صفحات -
تاریخ انتشار 2010