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

The main goal of this study is to obtain experimental data to develop adapted hydraulic and thermal wall functions used by industrial CFD codes. An experimental study, based on a test rig designed to reproduce realistic flow characteristics, has been conducted in order to explore velocity and temperature profiles. Hydraulic characterization of turbulent pipe flow was conducted over a Reynolds number range of 20 000 to 90 000, with three different test sections, presenting an increasing sand grain roughness. The three components of the flow velocity were measured, using laser Doppler velocimetry, and particle image velocimetry. The results obtained give access to turbulent quantities, to non-dimensional velocity profiles and to velocity defect in the boundary layer. These results are considered sufficient to cover the hydraulic requirements of an adequate wall-function related to surface roughness.

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The influence of suction on the structure of turbulence in fully developed pipe flow

Journal of Fluid Mechanics ◽

10.1017/s0022112079002081 ◽

1979 ◽

Vol 90 (1) ◽

pp. 67-107 ◽

Cited By ~ 54

Author(s):

M. Schildknecht ◽

J. A. Miller ◽

G. E. A. Meier

Keyword(s):

Energy Balance ◽

Cross Section ◽

Pipe Flow ◽

Friction Velocity ◽

Turbulent Energy ◽

Turbulent Pipe Flow ◽

List Type ◽

Entire Cross Section ◽

Uniform Wall ◽

Critical Layers

The effect of uniform wall suction on the structure of turbulence in a fully established turbulent pipe flow has been measured, with special attention to the critical layers close to the wall. Uniform suction was introduced into a pipe flow with a Reynolds number of 17250 by means of a porous-walled section 2·2 diameters in length with very fine perforations. The effect of suction on the turbulent energy balance was then measured over the entire cross-section at four axial locations. The results indicate the following.The amplitudes of the three principal velocity fluctuation components are reduced by suction, but to differing degrees. Moreover, the effects of suction on the amplitudes of these fluctuations develop at differing rates such that thex-wise components are first affected, then ther-wise and lastly the ϕ-wise components.The suction-induced perturbation in the turbulent structure propagates from the wall to the pipe centre-line with a velocity approximately equal to the friction velocityUτ.Even with very small rates of fluid extraction the maxima of the terms in the turbulent energy balance occurring close to the wall are drastically reduced. Nevertheless there is no tendency for the location of these maxima to move towards the wall.The general reduction of the level of turbulent energy across the entire section is due to transport of this energy by the augmented mean radial velocity towards the wall, where it is dissipated since the boundary condition inhibits the passage of turbulent energy through the wall.

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0120 Response of the Turbulent Pipe Flow to Sudden Change in Wall Roughness

The Proceedings of the Fluids engineering conference ◽

10.1299/jsmefed.2012.43 ◽

2012 ◽

Vol 2012 (0) ◽

pp. 43-44

Author(s):

Ryota KOJIMA ◽

Shinsuke MOCHIZUKI ◽

Takatsugu KAMEDA

Keyword(s):

Pipe Flow ◽

Sudden Change ◽

Turbulent Pipe Flow ◽

Wall Roughness

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