TRANSIENT TURBULENT FRICTION IN SMOOTH PIPE FLOWS

2003 ◽  
Vol 259 (5) ◽  
pp. 1011-1036 ◽  
Author(s):  
A.E. VARDY ◽  
J.M.B. BROWN
Keyword(s):  
Turbulent Friction ◽  
Pipe Flows ◽  
Smooth Pipe

Transient turbulent friction in fully rough pipe flows

2004 ◽  
Vol 270 (1-2) ◽  
pp. 233-257 ◽  
Author(s):  
A.E. Vardy ◽  
J.M.B. Brown
Keyword(s):  
Turbulent Friction ◽  
Pipe Flows

scholarly journals Numerical modelling of unsteady turbulent flow in tubes, including the effects of roughness and large changes in Reynolds number

2011 ◽  
Vol 225 (8) ◽  
pp. 1874-1885 ◽  
Author(s):  
D N Johnston
Keyword(s):  
Reynolds Number ◽  
Pipe Flow ◽  
Effective Viscosity ◽  
Method Of Characteristics ◽  
Turbulence Energy ◽  
Turbulent Friction ◽  
Pipe Flows ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Long Time

A method has been developed for predicting unsteady turbulent friction in smooth, transitional, and rough pipe flows. For transitional and rough pipe flows the effective viscosity at the wall is varied depending on Reynolds number and roughness. An approximation has been made for the transition region using a cubic spline for the friction factor between the smooth and rough regions. This turbulence model can be implemented readily in several types of numerical model for pipe flow, including simple lumped parameter models, finite difference/finite element methods, and the method of characteristics. An approximate method for representing changes in turbulence energy is discussed. Using this, the method is suitable for small and large changes in flow, and for short and long time scales, but further validation is needed.

A model for unsteady turbulent friction in pipe flows

2018 ◽  
Author(s):  
Douglas Monteiro Andrade ◽  
Felipe Bastos de Freitas Rachid
Keyword(s):  
Turbulent Friction ◽  
Pipe Flows

scholarly journals Asymptotic turbulent friction in 2D rough-walled flows

2021 ◽  
Vol 7 (5) ◽  
pp. eabc6234
Author(s):  
Alexandre Vilquin ◽  
Julie Jagielka ◽  
Simeon Djambov ◽  
Hugo Herouard ◽  
Patrick Fisher ◽  
...  
Keyword(s):  
Roughness Length ◽  
Soap Film ◽  
Standard Theory ◽  
Practical Relevance ◽  
Two Dimensional ◽  
Turbulent Friction ◽  
Spectral Exponent ◽  
Pipe Flows ◽  
Turbulent Spectrum ◽  
Film Flows

The friction f is the property of wall-bounded flows that sets the pumping cost of a pipeline, the draining capacity of a river, and other variables of practical relevance. For highly turbulent rough-walled pipe flows, f depends solely on the roughness length scale r, and the f − r relation may be expressed by the Strickler empirical scaling f ∝ r1/3. Here, we show experimentally that for soap film flows that are the two-dimensional (2D) equivalent of highly turbulent rough-walled pipe flows, f ∝ r and the f − r relation is not the same in 2D as in 3D. Our findings are beyond the purview of the standard theory of friction but consistent with a competing theory in which f is linked to the turbulent spectrum via the spectral exponent α: In 3D, α = 5/3 and the theory yields f ∝ r1/3; in 2D, α = 3 and the theory yields f ∝ r.

Wave evolution over a gradual slope with turbulent friction

1983 ◽  
Vol 133 ◽  
pp. 207-216 ◽  
Author(s):  
John W. Miles
Keyword(s):  
Friction Coefficient ◽  
Gravity Wave ◽  
Solitary Waves ◽  
Periodic Sequence ◽  
Relative Amplitude ◽  
Sinusoidal Wave ◽  
Turbulent Friction ◽  
Weakly Nonlinear ◽  
Wave Evolution

The evolution of a weakly nonlinear, weakly dispersive gravity wave in water of depth d over a bottom of gradual slope δ and Chezy friction coefficient Cf is studied. It is found that an initially sinusoidal wave evolves into a periodic sequence of solitary waves with relative amplitude a/d = α1 = 15δ/4Cf if α1 < αb, where αb is the relative amplitude above which breaking occurs. This prediction is supported by observations (Wells 1978) of the evolution of swell over mudflats.

Radial pressure forces in Euler-Euler simulations of turbulent bubbly pipe flows

2021 ◽  
Vol 374 ◽  
pp. 111079
Author(s):  
Roland Rzehak ◽  
Yixiang Liao ◽  
Richard Meller ◽  
Fabian Schlegel ◽  
Ronald Lehnigk ◽  
...  
Keyword(s):  
Radial Pressure ◽  
Pipe Flows

scholarly journals Perspective on the Response of Turbulent Pipe Flows to Strong Perturbations

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 208
Author(s):  
Liuyang Ding ◽  
Tyler Van Buren ◽  
Ian E. Gunady ◽  
Alexander J. Smits
Keyword(s):  
Pipe Flow ◽  
Abrupt Change ◽  
Pipe Wall ◽  
Surface Condition ◽  
Initial Response ◽  
Body Of Revolution ◽  
Future Directions ◽  
Pipe Flows ◽  
Roughness Elements ◽  
Pipe Geometry

Pipe flow responds to strong perturbations in ways that are fundamentally different from the response exhibited by boundary layers undergoing a similar perturbation, primarily because of the confinement offered by the pipe wall, and the need to satisfy continuity. We review such differences by examining previous literature, with a particular focus on the response of pipe flow to three different kinds of disturbances: the abrupt change in surface condition from rough to smooth, the obstruction due to presence of a single square bar roughness elements of different sizes, and the flow downstream of a streamlined body-of-revolution placed on the centerline of the pipe. In each case, the initial response is strongly influenced by the pipe geometry, but far downstream all three flows display a common feature, which is the very slow, second-order recovery that can be explained using a model based on the Reynolds stress equations. Some future directions for research are also given.

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