Journal ArticleDOI
Transient, turbulent, smooth pipe friction
Alan Vardy,Jim Brown +1 more
TLDR
In this paper, a weighting function model of transient friction is developed for flows in smooth pipes by assuming the turbulent viscosity to vary linearly within a thick shear layer surrounding a core of uniform velocity and is thus applicable to flows at high Reynolds number.Abstract:
Two of the most promising analytical models of unsteady friction in turbulent pipe flows are based on sharply contrasting hypotheses. One uses the history of the flow; the other uses instantaneous conditions. The purposes of this paper are to present an analysis using the former approach and to indicate how to determine which of the two methods is appropriate. A weighting function model of transient friction is developed for flows in smooth pipes by assuming the turbulent viscosity to vary linearly within a thick shear layer surrounding a core of uniform velocity and is thus applicable to flows at high Reynolds number. In the case of low Reynolds number turbulent flows and short time intervals, the predicted skin friction is identical to an earlier model developed by Vardy et al (1993). In the case of laminar flows, it gives results equivalent to those of Zielke (1966, 1968). The predictions are compared with analytical results for the special case of flows with uniform acceleration. It is this case that ...read more
Citations
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Journal ArticleDOI
A Review of Water Hammer Theory and Practice
TL;DR: In this paper, the authors present an overview of both historic developments and present research and practice in the field of hydraulic transients, including mass and momentum equations for one-dimensional flows.
Journal ArticleDOI
Developments in unsteady pipe flow friction modelling
TL;DR: In this paper, two distinct unsteady friction models, the Zielke and the Brunone models, are investigated in detail, and the two models are incorporated into the method of characteristics water hammer algorithm.
Journal ArticleDOI
Transient turbulent friction in smooth pipe flows
Alan Vardy,Jim Brown +1 more
TL;DR: In this article, a weighting function model of unsteady skin friction in smooth-walled, one-dimensional ducts is derived using an idealized form of the radial viscosity distribution.
Journal ArticleDOI
The dynamic effect of pipe-wall viscoelasticity in hydraulic transients. Part II—model development, calibration and verification
TL;DR: In this article, a new nouveau modele hydraulique (nomme HTS) was developed for calculating regimes transitoires hydrauliques des systemes de conduites pressurisees in polyethylene (PE).
Journal ArticleDOI
Velocity Profiles and Unsteady Pipe Friction in Transient Flow
TL;DR: In this paper, the velocity profiles recorded during these transient events clearly show regions of flow recirculation, flow reversal, and an increased intensity of fluid turbulence, and the experimental pressures are compared to a water hammer model using a conventional quasi-steady representation of head loss.
References
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The Structure of Turbulence in Fully Developed Pipe Flow
TL;DR: In this paper, a hot-wire anemometer was used to measure the turbulent flow in a 10-inch pipe at speeds of approximately 10 and 100 feet per second, and the results include relevant mean and statistical quantities, such as Reynolds stresses, triple correlations, turbulent dissipation, and energy spectra.
Journal ArticleDOI
An Efficient Method for Simulating Frequency-Dependent Friction in Transient Liquid Flow
Journal ArticleDOI
The Effect of Viscous Shear on Transients in Liquid Lines
E. L. Holmboe,W. T. Rouleau +1 more
Journal ArticleDOI
A weighting function model of transient turbulent pipe friction
Alan Vardy,Kuo-Lun Hwang +1 more
TL;DR: In this article, a weighting function model of transient turbulent pipe friction at moderate Reynolds Numbers is developed in a similar manner to Zielke's equivalent expression for laminar flow.