Velocity profiles in constant-acceleration pipe flows

Rapid transition to turbulence in a pipe flow, initially at rest, was achieved by temporally accelerating the flow and then sharply decelerating it to its final Reynolds number. The acceleration phase was characterized by the growth of a laminar boundary layer close to the wall. The subsequent rapid deceleration resulted in inflectional velocity profiles near the wall, followed immediately by transition to turbulence. The time taken to transition was significantly less than the time to transition in a pipe flow monotonically accelerated to the same Reynolds number. Transition is intrinsically different to that observed in oscillatory pipe flows, but is qualitatively similar to pipe flows decelerated to rest.

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Velocity Profiles and Friction Factors in Turbulent Pipe Flows

Rheology of Drag Reducing Fluids ◽

10.1007/978-3-030-40045-3_2 ◽

2020 ◽

pp. 39-67

Author(s):

Aroon Shenoy

Keyword(s):

Velocity Profiles ◽

Pipe Flows ◽

Friction Factors

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Some Considerations on Velocity Profiles in Unsteady Pipe Flows

Entropy and Energy Dissipation in Water Resources - Water Science and Technology Library ◽

10.1007/978-94-011-2430-0_28 ◽

1992 ◽

pp. 481-487 ◽

Cited By ~ 4

Author(s):

Bruno Brunone ◽

Umberto M. Golia

Keyword(s):

Velocity Profiles ◽

Pipe Flows

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A Similarity of the Velocity Profiles According to Water Depth in Partially Filled Circular Pipe Flows

Journal of the Korean Society of Visualization ◽

10.5407/jksv.2008.6.2.028 ◽

2008 ◽

Vol 6 (2) ◽

pp. 28-32

Author(s):

Ji-In Yoon ◽

Young-Bae Kim ◽

Jae-Yong Sung ◽

Myeong-Ho Lee

Keyword(s):

Water Depth ◽

Velocity Profiles ◽

Circular Pipe ◽

Pipe Flows

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Determination of velocity profiles in oscillating pipe-flows by using laser Doppler velocimetry and ultrasonic measuring devices

Flow Measurement and Instrumentation ◽

10.1016/0955-5986(92)90006-q ◽

1992 ◽

Vol 3 (2) ◽

pp. 95-101 ◽

Cited By ~ 18

Author(s):

M. Teufel ◽

D. Trimis ◽

A. Lohmüller ◽

Y. Takeda ◽

F. Durst

Keyword(s):

Laser Doppler Velocimetry ◽

Velocity Profiles ◽

Laser Doppler ◽

Doppler Velocimetry ◽

Pipe Flows ◽

Measuring Devices ◽

Ultrasonic Measuring

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Wall skin friction and mean velocity profiles of fully developed turbulent pipe flows

Experimental Thermal and Fluid Science ◽

10.1016/j.expthermflusci.2007.04.002 ◽

2007 ◽

Vol 32 (1) ◽

pp. 249-261 ◽

Cited By ~ 17

Author(s):

E.-S. Zanoun ◽

F. Durst ◽

O. Bayoumy ◽

A. Al-Salaymeh

Keyword(s):

Skin Friction ◽

Velocity Profiles ◽

Mean Velocity ◽

Pipe Flows

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Further Experiments on Transition to Turbulence in Constant-Acceleration Pipe Flow

Journal of Fluids Engineering ◽

10.1115/1.2909484 ◽

1991 ◽

Vol 113 (2) ◽

pp. 223-227 ◽

Cited By ~ 11

Author(s):

P. J. Lefebvre ◽

F. M. White

Keyword(s):

Empirical Equation ◽

Previous Experiment ◽

Transition To Turbulence ◽

Constant Acceleration ◽

Pipe Flows ◽

Order Of Magnitude ◽

Current Experimental Data ◽

Series Of Experiments ◽

Correlation Parameters ◽

Reported Data

A second series of experiments was conducted to extend and validate recently reported data by the present authors on transition to turbulence in pipe flows started from rest under constant acceleration. The test section diameter was increased from the 5 cm of the previous experiment to 9 cm for the present study. The low end of the acceleration range was also extended by an order of magnitude from 1.8 m/s2 down to 0.2 m/s2. The highest acceleration was 11.2 m/s2. Pipe Reynolds number at transition was observed to be as high as 1.1 × 106. The present results are shown to validate the previously suggested transition correlation parameters. An analysis based on an empirical equation for transition in convectively accelerated flows is extended and applied to the current experimental data.

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