*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. Bershadskii**

^{1, 2}, K. R. Sreenivasan^{1}and J. J. Niemela^{1}^{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

** Abstract **

Using experimental data on thermal convection, obtained at a
Rayleigh number of 1.5
, it is shown that the
temperature structure functions
,
where
is the absolute value of the temperature
increment over a distance
*r*, can be well represented in an
intermediate range of scales by
,
where the
are the scaling exponents appropriate to the
passive scalar problem in hydrodynamic turbulence and the function
. Measurements are made in the
midplane of the apparatus near the sidewall, but outside the
boundary layer.

**PACS**

47.27.Te - Convection and heat transfer.

47.27.Jv - High-Reynolds-number turbulence.

**©**

*EDP Sciences 2005*