Europhys. Lett.
Volume 69, Number 1, January 2005
Page(s) 75 - 80
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 08 December 2004
Europhys. Lett., 69 (1), pp. 75-80 (2005)
DOI: 10.1209/epl/i2004-10373-4

Logarithmically modified scaling of temperature structure functions in thermal convection

A. Bershadskii1, 2, K. R. Sreenivasan1 and J. J. Niemela1

1  International Center for Theoretical Physics - Strada Costiera 11, 34100 Trieste, Italy
2  ICAR - P.O. Box 31155, Jerusalem 91000, Israel

received 29 April 2004; accepted in final form 3 September 2004
published online 8 December 2004

Using experimental data on thermal convection, obtained at a Rayleigh number of 1.5 $\times 10^{11}$, it is shown that the temperature structure functions $\langle \Delta T_{r}^p \rangle$, where $\Delta T_r$ is the absolute value of the temperature increment over a distance r, can be well represented in an intermediate range of scales by $r^{\zeta_p} \varphi (r)^{p}$, where the $\zeta_p$ are the scaling exponents appropriate to the passive scalar problem in hydrodynamic turbulence and the function $\varphi (r) = 1-a(\ln r/r_h)^2$. Measurements are made in the midplane of the apparatus near the sidewall, but outside the boundary layer.

47.27.Te - Convection and heat transfer.
47.27.Jv - High-Reynolds-number turbulence.

© EDP Sciences 2005