| Abstract: | The turbulence characteristics of very small (compared with the exterior scale of the flow) vortices in a developed turbulent boundary layer can be described with good accuracy by the Kolmogorov—Obukhov theory of locally isotropic turbulence. However, it does not apply to turbulent disturbances of large scale, for which the pulsations of the velocity and the temperature cannot be assumed to be isotropic. The aim of the present paper is to investigate the spectral and correlation characteristics of the turbulent field of the velocities and temperatures in the logarithmic sublayer of a gradientless flow for scales appreciably less than the boundary layer thickness but greater than the value below which the assumption of local isotropy holds. Attention is drawn to the part played by the interior turbulence scale (under the considered conditions, the distance to the wall), which distinguishes the  hyperbolic law of variation of the spectrum characteristic of anisotropic pulsations of the velocity and the temperature and the five-thirds power law for isotropic vortices. Comparison of the derived relations with the available experimental data makes it possible not only to verify the validity of these laws but also to determine the values of the universal constants in them. The stability of the obtained laws with respect to disturbances localized in the wall region (roughness, blowing and suction, polymer additives, etc.) is discussed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 47–56, January–February, 1984.I am very grateful to A. M. Yaglom for his interest in the work and for discussing the results. |
