On the behaviour of periodic disturbances introduced into a turbulent channel flow by an oscillating airfoil

Abstract

This paper is on the propagation characteristics of disturbances in turbulent shear flow. Periodic disturbances are introduced into a fully developed turbulent channel flow by an airfoil executing pitching oscillations. Hot-wire measurements are done on the mean and fluctuating velocities, on the Reynolds stresses and their spectra. The spectral data are evaluated to obtain the decay characteristics of the induced disturbance in this flow. The results show that the disturbance propagation in this flow is characterised by different decay rates in the regions near and far from the disturbance source.