Study of the Outer Self-regeneration of Turbulence in Wall Flows

A new approach for the study of the overlap layer of wallturbulence is proposed. The multi-dimensional description of turbulence given by the Kolmogorov equation generalized to wall-flows is used and shown relevant for the identification of very robust features of the overlap layer. Numerical data of a turbulent channel are used. Despite the low Reynolds, a well-defined outer energy source region appears. The possibility to analyze its effects on the energy tranfer among scales and wall-distances is shown important to clarify the influences of the external region on the inner layer.