Volume 79, Number 4, August 2007
Article Number 44001
Number of page(s) 5
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
Published online 26 July 2007
EPL, 79 (2007) 44001
DOI: 10.1209/0295-5075/79/44001

Scaling of mixed longitudinal-transverse velocity structure functions

G. Xu1, R. A. Antonia2 and S. Rajagopalan2

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

Measurements in a turbulent round jet at a Taylor microscale Reynolds number $R_{\lambda }$ 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 $\theta $ exhibits a smaller departure from the Kolmogorov scaling than either u or $\theta $ 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 $(\partial u/\partial x)^{2}$ and either $(\partial v/\partial x)^{2}$ or $(\partial \theta /\partial x)^{2}$, implying that there is an important difference between temperature and velocity fields.

47.27.wg - Turbulent jets.
47.27.-i - Turbulent flows.

© Europhysics Letters Association 2007