The mechanics of an organized wave in turbulent shear flow

TLDR

Controlled wave disturbances in turbulent channel flow are investigated. Weak plane‑wave disturbances are generated by vibrating ribbons near the walls, and their amplitude, phase, speed, attenuation, and shape are measured downstream using hot‑wire signals. Analysis of the data reveals the normal component and wave Reynolds stress, indicating that existing Orr–Sommerfeld theories are inadequate for describing these waves.

Abstract

Some preliminary results on the behaviour of controlled wave disturbances introduced artificially into turbulent channel flow are reported. Weak plane-wave disturbances are introduced by vibrating ribbons near each wall. The amplitude and relative phase of the streamwise component of the induced wave is educed from a hot wire signal, allowing the wave speed and attenuation characteristics and the wave shape to be traced downstream. The normal component and wave Reynolds stress have been inferred from these data. It appears that Orr–Sommerfeld theories attempted to date are inadequate for description of these waves.