Turbulence Characteristics in Gradual Channel Transition
Publication: Journal of Engineering Mechanics
Volume 128, Issue 9
Abstract
A field study was conducted to determine the effects of a channel transition on turbulence characteristics. Detailed three-dimensional (3D) flow measurements were collected at a cross section that is located downstream of a gradual channel expansion. These measurements were obtained via an acoustic doppler velocimeter and include the 3D velocity field, the mean local velocities, the turbulent intensities, the frictional characteristics of the flow, the secondary velocity along the transverse plane, and the instantaneous shear stress components in the streamwise and transverse directions. Analysis of the 3D flow data indicates that the turbulent flow on the outer bank of the channel is anisotropic. Such anisotropy of turbulence, which is attributed to the gradual expansion in the channel and bed roughness, yields the development of a secondary flow of Prandtl’s second kind as reported in 1952. In particular, it was found that turbulent intensities in the vertical and transverse directions on the outer bank section are different in magnitude creating turbulence anisotropy in the cross-sectional plane and secondary flows of the second kind. Turbulent intensities increase toward the free surface indicating the transfer of a higher-momentum flux from the channel bed to the free surface, which contradicts common wisdom. Results for the normalized stress components in the streamwise and transverse direction show similar behavior to the intensities. Moreover, the nonlinear distribution of stresses is indicative of the oscillatory nature of the flow induced by the secondary flows of Prandtl’s second kind. A similar behavior was found for flows in straight rectangular channels over different roughness. Finally, a comparison between the secondary current velocity with the mainstream velocity indicates that secondary flow of Prandtl’s second kind is present within the right half of the measured cross section.
Get full access to this article
View all available purchase options and get full access to this article.
References
Afzalimhehr, H., and Anctil, F.(2000). “Accelerating shear velocity in gravel-bed channels.” Hydro. Sci. J., 45(1), 113–124.
Alt, D. D., and Hyndman, D. W. (1998). Roadside geology of Washington, Mountain Press.
Anderson, A., Paintal, A., and Davenport, J. (1970). “Tentative design procedure for riprap lined channels. NCHRP Rep. 108, Highway. Research Board, National Academy of Engineering, Washington, D.C.
Brundrett, E., and Baines, W.(1964). “The production and diffusion of vorticity in duct flow.” J. Fluid Mech., 19(3), 375–394.
Chen, C., and Jaw, S. (1997). Fundamentals of turbulence modeling, Taylor & Francis, London.
Clauser, F.(1956). “The turbulent boundary layer.” Adv. Appl. Mech., 4, 1–51.
Dancey, C. L.(1990). “Measurement of second order turbulence statistics in an axial flow compressor via 3-component LDA.” AIAA J., 90, 2017.
Ead, S., Rajaratnam, N., Katopodis, C., and Ade, F.(2000). “Turbulent open channel flow in circular corrugated culverts.” J. Hydraul. Eng., 126(10), 750–757.
El-Shewey, M. I. A., and Joshi, S. G.(1996). “A study of turbulence characteristics in open channel transitions as a function of Froude and Reynolds numbers using laser technique.” Adv. Fluid Mech., 9, 363–372.
Goldstein, R., Eriksen, V., Olson, R., and Eckert, E. (1970). “Laminar separation, reattachment, and transition of the flow over a downstream-facing step.” J. Basic Eng., 92,
Grass, A. J. (1983). The influence of boundary layer turbulence on the mechanics of sediment transport, B. M. Sumer, and A. Muller, eds., A. A. Balkema, Rotterdam, The Netherlands, 3–17.
Hicks, M., and Mason, P. (1998). Roughness characteristics of New Zealand rivers, NIWA.
Hitoshi, S., Akiyama, M., Mitsunobu, F. O., and Sato, T.(1995). “Numerical analysis of developing turbulent flow in a square-sectioned 90 degree bend.” Trans. Jpn. Soc. Mech. Eng., Ser. B, 61(587), 2393–2400.
Ikeda, S.(1981). “Self-forced straight channels in sandy beds.” J. Hydraul. Div., Am. Soc. Civ. Eng., 107(4), 389–406.
Karcz, I.(1967). “Harrow marks, current-aligned sedimentary structures.” J. Geol., 75, 113–121.
Kim, J., Kline, S., and Johnston, J. P.(1980). “Investigation of a reattaching turbulent shear layer: Flow over a backward-facing step.” J. Fluids Eng., 102, 302.
Kironoto, B. A., and Graf, W. H. (1994). “Turbulence characteristics in rough uniform open-channel flow.” Proc., Inst. Civ. Eng., Waters, Maritime Energ., 98.
Kline, S. J., Reynolds, W. C., Schraub, F. A., and Runstadler, P. W.(1967). “The structure of turbulent boundary layers.” J. Fluid Mech., 30, 741–773.
Knight, D., Demetriou, J., and Hamed, M.(1984). “Boundary shear in smooth rectangular channels.” J. Hydraul. Eng., 110(4), 405–422.
Lai, Y., So, R., Anwer, M., and Hwang, B.(1991). “Calculations of a curved-pipe flow using Reynolds stress closure.” Proc. Inst. Mech. Eng., 205, 231–243.
McLelland, S., Ashworth, P., Best, J., and Livesey, J.(1999). “Turbulence and secondary flow over sediment stripes in weakly bimodal bed material.” J. Secondary Flows, 125(5), 463–473.
Mehta, P. R.(1981). “Separated flow through large sudden expansions.” J. Hydraul. Div., Am. Soc. Civ. Eng., 107(4), 451–460.
Montgomery, D., and Buffington, J. (1993). “Channel classification, prediction of channel response, and assessment of channel condition.” Rep. No. THW-SH19-93-002, prepared by SHAMW Committee of the Washington State Timber/Fish/Wildlife Agreement.
Morris, H.(1955). “Flow in rough conditions.” Trans. Am. Soc. Civ. Eng., 120, 373–398.
Naden, P.(1987). “An erosion criterion for gravel-bed rivers.” Earth Surf. Processes Landforms, 12, 83–93.
Naot, D., and Rodi, W.(1982). “Calculation of secondary currents in channel flow.” J. Hydraul. Eng., 108(8), 948–968.
Nezu, I., and Nakagawa, H. (1993). Turbulence in open channel flows, A. A. Balkema, Rotterdam, The Netherlands.
Papanicolaou, A. (1997). “The role of turbulence on the initiation of sediment motion.” PhD dissertation, Virginia Polytechnic Institute and State Univ., Blacksburg, Va.
Papanicolaou, A., Diplas, P., Dancey, C., and Balakrishnan, M.(2001). “Surface roughness effects in near-bed turbulence: Implications to sediment entrainment.” J. Eng. Mech., 127(3), 211–218.
Prandtl, L. (1952). Uber die ausgebildete Turbulenz. ZAMM, Vol. 5. Missoula, MT, Rotterdam, The Netherlands, 136.
Schlichting, H. (1968). Boundary layer theory, 6th Ed. McGraw-Hill, New York.
Song, T., and Chiew, Y.(2001). “Turbulence measurement in nonuniform open-channel flow using acoustic doppler velocimeter (ADV).” J. Eng. Mech., 127(3), 219–231.
Song, T., Graf, W. H., and Lemmin, U.(1994). “Uniform flow in open channels with movable gravel bed.” J. Hydraul. Res., 32(6), 861–876.
Sukhodolov, A., Thiele, M., and Bungartz, H.(1998). “Turbulence structure in a river reach with sand beds.” Water Resour. Res., 34(5), 1317–1334.
Thorne, C., and Zevenbergen, L.(1985). “Estimating mean velocity in mountain rivers.” J. Hydraul. Eng., 111(4), 612–624.
White, F. (1991). Viscous fluid flow, 2nd Ed., McGraw-Hill, New York.
Yen, B. C. (1965). “Characteristics of subcritical flow in meandering channel.” Report prepared at the Institute of Hydraulic Research, Univ. of Iowa, Iowa City, Iowa.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 128 • Issue 9 • September 2002
Pages: 948 - 960
Copyright
Copyright © 2002 American Society of Civil Engineers.
History
Received: May 22, 2001
Accepted: Jan 23, 2002
Published online: Aug 15, 2002
Published in print: Sep 2002
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.