Turbulent pipe flow: Statistics,Re-dependence, structures and similarities with channel and boundary layer flows

An improvement of the k-ε model has been made in conjunction with an accurate prediction of the near-wall limiting behavior of turbulence and the final period of the decay law of free turbulence. The present improved k-ε model has been extended to predict the effects of adverse pressure gradients on shear layers, which most previously proposed models failed to do correctly. The proposed model was tested by application to a turbulent pipe flow, a flat plate boundary layer, a relaminarizing flow, and a diffuser flow with a strong adverse pressure gradient. Agreement with the experiments was generally very satisfactory.

Download Full-text

Large- and very-large-scale motions in channel and boundary-layer flows

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2006.1940 ◽

2007 ◽

Vol 365 (1852) ◽

pp. 665-681 ◽

Cited By ~ 252

Author(s):

B.J Balakumar ◽

R.J Adrian

Keyword(s):

Boundary Layer ◽

Shear Stress ◽

Pipe Flow ◽

Large Scale ◽

Reynolds Shear Stress ◽

Boundary Layer Flows ◽

Wall Flows ◽

Large Structures ◽

Measurement And Analysis ◽

Common Behaviour

Large-scale motions (LSMs; having wavelengths up to 2–3 pipe radii) and very-LSMs (having wavelengths more than 3 pipe radii) have been shown to carry more than half of the kinetic energy and Reynolds shear stress in a fully developed pipe flow. Studies using essentially the same methods of measurement and analysis have been extended to channel and zero-pressure-gradient boundary-layer flows to determine whether large structures appear in these canonical wall flows and how their properties compare with that of the pipe flow. The very large scales, especially those of the boundary layer, are shorter than the corresponding scales in the pipe flow, but otherwise share a common behaviour, suggesting that they arise from similar mechanism(s) aside from the modifying influences of the outer geometries. Spectra of the net force due to the Reynolds shear stress in the channel and boundary layer flows are similar to those in the pipe flow. They show that the very-large-scale and main turbulent motions act to decelerate the flow in the region above the maximum of the Reynolds shear stress.

Download Full-text

The Preston tube as a means of measuring skin friction

Journal of Fluid Mechanics ◽

10.1017/s0022112062001020 ◽

1962 ◽

Vol 14 (1) ◽

pp. 1-17 ◽

Cited By ~ 63

Author(s):

M. R. Head ◽

I. Rechenberg

Keyword(s):

Boundary Layer ◽

Turbulent Boundary Layer ◽

Skin Friction ◽

Pipe Flow ◽

Large Diameter ◽

Turbulent Pipe Flow ◽

Pitot Tube ◽

Diameter Pipe ◽

Flow Similarity ◽

Considerable Doubt

Preston's method of measuring skin friction, which makes use of a Pitot tube resting on the surface, depends upon the assumption of a region of flow similarity, adjacent to the wall, common to fully developed turbulent pipe flow and the turbulent boundary layer. Experiments performed elsewhere have cast considerable doubt on the validity of this assumption, and the present investigation was undertaken to establish whether or not it is justified.Experiments were carried out in a short length of large-diameter pipe which could either form part of a very much longer pipe, giving fully developed turbulent pipe flow, or could be preceded by a conventional contraction and screens, giving a developing turbulent boundary layer.Final results showed that for a given skin friction the Pitot tube reading was the same for both boundary layer and pipe flows, thus vindicating Preston's method and confirming the existence of a universal region of wall similarity. Initial experimental difficulties were found to be due to unexpectedly large circumferential variations in skin friction in the growing boundary layer.

Download Full-text

Further Experiments With Suction at a Sudden Enlargement in a Pipe

Journal of Basic Engineering ◽

10.1115/1.3425025 ◽

1970 ◽

Vol 92 (3) ◽

pp. 437-447 ◽

Cited By ~ 4

Author(s):

Gunnar Heskestad

Keyword(s):

Boundary Layer ◽

Pipe Flow ◽

Expansion Ratio ◽

Turbulent Pipe Flow ◽

Thin Boundary Layer ◽

Inlet Flow ◽

Upper Limit ◽

Sudden Enlargement ◽

Flow Through ◽

And Performance

Previously reported experiments on incompressible flow through a step expansion in a pipe, as influenced by suction at the smaller diameter of the step, have been extended to examine effects of inlet flow on suction requirements and performance of the device as a (short) diffuser. Here the performance for a fully developed turbulent pipe flow is considered and compared to previous results for an inlet flow with thin boundary layer. Whenever overall diffuser length is restricted to values less than some upper limit for a given expansion ratio, then for either inlet flow condition, the present device is shown to produce higher pressure recoveries (adjusted for suction power) than conical diffusers.

Download Full-text

Experimental determination of the random lump-age distribution in the boundary layer of the turbulent pipe flow using laser-doppler anemometry

Chemical Engineering Science ◽

10.1016/0009-2509(83)80158-4 ◽

1983 ◽

Vol 38 (3) ◽

pp. 399-424 ◽

Cited By ~ 10

Author(s):

H.R.E. Van Maanen ◽

J.M.H. Fortuin

Keyword(s):

Boundary Layer ◽

Experimental Determination ◽

Pipe Flow ◽

Laser Doppler Anemometry ◽

Age Distribution ◽

Turbulent Pipe Flow ◽

Laser Doppler

Download Full-text

Deposition Process and Equivalent Markov Motion of High-inertia Particles in a Long Straight Pipeline

Journal of Fluids Engineering ◽

10.1115/1.4051387 ◽

2021 ◽

Author(s):

Ri Zhang ◽

Kai Xu ◽

Yong Liu ◽

Yumiao Wang

Keyword(s):

Boundary Layer ◽

Monte Carlo ◽

Monte Carlo Method ◽

Pipe Flow ◽

Particle Deposition ◽

Deposition Velocity ◽

Deposition Process ◽

Turbulent Pipe Flow ◽

Probability Density Distribution ◽

The Monte Carlo Method

Abstract Two methods are used to study the process of particle deposition in a turbulent pipe flow. The Monte Carlo method tracks 10,000 particles in the turbulent pipe flow to reproduce the deposition process of the particles. The deposition velocity of the particles is determined by calculating the proportion of particles passing through the test section. The simplified deposition model uses an equivalent Markov motion instead of the radial movement of the particle in the turbulent core. The probability that a particle leaves the turbulent core depends on the radial particle position and the probability density distribution of the random vortex. The probability that a particle penetrates the boundary layer can be solved by integrating the probability density distribution of radial particle velocity. The deposition velocity of particles can be obtained by calculating the probability of an individual particle leaving the turbulent core and penetrating the boundary layer. Five experimental data series from the literature are applied to examine the predictive abilities of the two methods. The results demonstrate that the Monte Carlo method can be properly used to track the particle deposition process in the diffusion-impaction and inertia-moderated regimes. The simplified model is suitable for high-inertia particles.

Download Full-text