TURBULENCE MODULATION BY WALL PERMEABILITY IN A WALL-BOUNDED FLOW

Wall-bounded turbulence

Relationship between Turbulence Modulation and Skewness in Wall Bounded Flows

Recent investigations into wall-bounded turbulent flows have shown a nonlinear scale interaction, whereby the largescale motion amplitude modulates the small-scale structures (Hutchins & Marusic, 2007b). Mathis et al. (2009) developed a scheme to quantify the degree of modulation using a decoupling procedure, based on the Hilbert transformation applied to the filtered small-scale component of t...

Coherent structures in wall-bounded turbulence.

The inherent difficulty of understanding turbulence has led to researchers attacking the topic in many different ways over the years of turbulence research. Some approaches have been more successful than others, but most only deal with part of the problem. One approach that has seen reasonable success (or at least popularity) is that of attempting to deconstruct the complex and disorganised tur...

Drag reduction by polymers in wall bounded turbulence.

We elucidate the mechanism of drag reduction by polymers in turbulent wall-bounded flows: while momentum is produced at a fixed rate by the forcing, polymer stretching results in the suppression of momentum flux to the wall. On the basis of the equations of fluid mechanics we develop the phenomenology of the "maximum drag reduction asymptote" which is the maximum drag reduction attained by poly...

Phenomenology of wall-bounded Newtonian turbulence.

We construct a simple analytic model for wall-bounded turbulence, containing only four adjustable parameters. Two of these parameters are responsible for the viscous dissipation of the components of the Reynolds stress tensor. The other two parameters control the nonlinear relaxation of these objects. The model offers an analytic description of the profiles of the mean velocity and the correlat...