On skin friction in wall-bounded turbulence

Wall-bounded turbulence

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...

Skin Friction in Simple Wall - Bounded Shear Flows in Large Reynolds Number Limit

Expressions for variation of skin friction with Reynolds number in fully developed turbulent channel/pipe flows and in zero pressure gradient boundary layers are derived. The proposed in this paper asymptotic (Reδ = δ(x)U ν → ∞) theory is formulated as a convergent perturbation expansion in powers of small dimensionless parameters dδ dx → 0 and u∗ U → 0 applied directly to the Navier-Stokes equ...

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...

The Topology of Surface Skin Friction and Vorticity Fields in Wall-bounded Flows

In previous studies, the three invariants of the velocity gradient tensor have been used to study turbulent flow structures. For incompressible flow the first invariant P is zero and the topology of the flow structures can be investigated in terms of the second and third invariants, Q and R respectively. However, these invariants are zero at a no slip wall and can no longer be used to identify ...