**79**(2007) 44001

DOI: 10.1209/0295-5075/79/44001

## Scaling of mixed longitudinal-transverse velocity structure functions

**G. Xu**

^{1}, R. A. Antonia^{2}and S. Rajagopalan^{2}^{1}School of Civil Engineering, University of Sydney - NSW 2006, Australia

^{2}Discipline of Mechanical Engineering, University of Newcastle - NSW 2308, Australia

received 6 March 2007; accepted in final form 3 July 2007; published August 2007

published online 26 July 2007

** Abstract **

Measurements in a turbulent round jet at a Taylor microscale Reynolds number
of about 500 indicate that the mixed structure functions of *u*, the longitudinal velocity fluctuation, and *v*, the transverse velocity fluctuation, show a larger departure from the Kolmogorov scaling than the *u* structure functions, and a smaller departure than the *v* structure functions. Although the scaling exponents of the temperature structure functions are nearly equal to those of the *v* structure functions at a comparable order, the mixed structure functions of *u* and the temperature fluctuation exhibits a smaller departure from the Kolmogorov scaling than either *u* or structure functions at the same order. The difference between the scaling behaviour of these two mixed structure functions mainly reflects the difference in correlation between
and either
or
, implying that there is an important difference between temperature and velocity fields.

**PACS**

47.27.wg - Turbulent jets.

47.27.-i - Turbulent flows.

**©**

*Europhysics Letters Association 2007*