Unified Wall Function and Application for Steady Turbulent Pipe Flow with Uniform Wall Roughness

Roughness effects on wall-bounded turbulent flowsa)

This paper outlines the authors’ experimental research in rough-wall-bounded turbulent flows that has spanned the past 15 years. The results show that, in general, roughness effects are confined to the inner layer. In accordance with Townsend’s Reynolds number similarity hypothesis, the outer layer is insensitive to surface condition except in the role it plays in setting the length and velocit...

Predictive model for wall-bounded turbulent flow.

The behavior of turbulent fluid motion, particularly in the thin chaotic fluid layers immediately adjacent to solid boundaries, can be difficult to understand or predict. These layers account for up to 50% of the aerodynamic drag on modern airliners and occupy the first 100 meters or so of the atmosphere, thus governing wider meteorological phenomena. The physics of these layers is such that th...

Turbulent flow over a long flat plate with uniform roughness

For turbulent boundary-layer flow under a uniform freestream speed U∞ over a plate of length L, covered with uniform roughness of nominal sand-grain scale ks , the physical behaviors underlying two distinguished limits at large ReL ≡ U∞L/ν are explored: the fully rough wall flow where ks/L is fixed and the long-plate limit where Rek ≡ U∞ks/ν is fixed. For the fully rough limit it is shown that ...

Wall corrections in modeling rotating pipe flow

numerical simulation of turbulent flow and heat transfer in a b-type section pipe with porous bottom wall

in this work, three-dimensional turbulent forced convection flow through a b-type section pipe, which porous material inserted at the bottom wall, is investigated numerically. the b-type section pipe are used in cooling systems, such as cars’ radiators. the main purpose of this research is to enhance heat transfer and to reduce the scales of such systems. the governing equations are formulated ...