2D Modeling of Heterogeneous Dispersion in Meandering Channels
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 2
Abstract
Two types of dispersion coefficient tensor for meandering channels were examined. The first type was estimated using measured vertical velocity profile in an S-curved channel, and the second type was based on the depth-averaged velocity field. A Petrov-Galerkin type finite element scheme was used in the numerical modeling, and the simulation results were compared with the experimental results from tracer tests in an S-curved channel. Comparison of the results show that the dispersion coefficient tensor obtained directly from velocity profiles provided a more realistic solution that can describe the abrupt expansion of tracer clouds in the transverse direction. Heterogeneous longitudinal and transverse dispersion coefficients were inversely estimated from the calculated dispersion coefficient tensor based on the velocity profiles. Extremely large transverse dispersion coefficients were formed at the apex of the channel bend, where there was a well-developed secondary current. The dimensionless transverse dispersion coefficient in the apex of the bend ranges from 0.495 to 2.60, which is about four times larger than that of the straight region.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This research was supported by the 21C Frontier Project of the Korean Ministry of Science and TechnologyKMST and by Grant No. KSEFR01-2006-000-11027-0 from the Basic Research Program of the Korea Science and Engineering Foundation. This research was conducted at the Research Institute of Engineering Science of Seoul National University, Seoul, Korea. The writers wish to thank Mr. K. H. Sung and S. J. Jeong for carrying out the laboratory experiments.
References
Alavian, V. (1986). “Dispersion tensor in rotating flows.” J. Hydraul. Eng., 112(8), 771–777.
Ashan, A. K. M. Q., Bruno, M. S., Oey, L.-Y., and Hires, R. (1994). “Wind-driven dispersion in New Jersey coastal waters.” J. Hydraul. Eng., 120(11), 1264–1273.
Baek, K. O. (2004). “Transverse mixing in meandering channels with unsteady pollutant source.” Ph.D. thesis, Seoul Nat. Univ., Seoul, Korea.
Boxall, J. B., and Guymer, I. (2003). “Analysis and prediction of transverse mixing coefficients in natural channels.” J. Hydraul. Eng., 129(2), 129–139.
Boxall, J. B., Guymer, I., and Marion, A. (2003). “Transverse mixing in sinuous natural open channel flows.” J. Hydraul. Res., 41(2), 153–165.
Chang, Y. C. (1971). “Lateral mixing in meandering channels.” Ph.D. thesis, Univ. of Iowa, Iowa City, Iowa.
Cheng, R. T., Casulli, V., and Milford, S. W. (1984). “Eulerian-Lagrangian solution of the convective-dispersion equation in natural coordinates.” Water Resour. Res., 20(7), 944–952.
Chow, V. T. (1959). Open-channel hydraulics, McGraw-Hill, New York.
Day, T. J. (1975). “Longitudinal dispersion in natural channels.” Water Resour. Res., 11(6), 909–918.
Duan, G. (2004). “Simulation of flow and mass dispersion in meandering channels.” J. Hydraul. Eng., 130(10), 964–976.
Elder, J. W. (1959). “The dispersion of marked fluid in turbulent shear flow.” J. Fluid Mech., 5, 544–560.
Fischer, H. B. (1978). “On the tensor form of the bulk dispersion coefficient in a bounded skewed shear flow.” J. Geophys. Res., C: Oceans Atmos., 83(C5), 2373–2375.
Fischer, H. B., List, E. J., Koh, R. C. Y., Imberger, J., and Brooks, N. H. (1979). Mixing in inland and coastal waters, Academic, London.
Guymer, I. (1998). “Longitudinal dispersion in sinuous channel with changes in shape.” J. Hydraul. Eng., 124(1), 33–40.
Jobson, H. E., and Sayre, W. W. (1970). “Predicting concentration profiles in open channels.” J. Hydr. Div., 96(10), 1983–1996.
Krishnappan, B. G., and Lau, Y. L. (1977). “Transverse mixing in meandering channels with varying bottom topography.” J. Hydraul. Res., 15(4), 351–371.
Leopold, L. B., and Wolman, M. G. (1960). “River meanders.” Bulletine of the Geological Society of America, 71, 769–794.
Marivoet, J. L., and Van Craenenbroeck, W. (1986). “Longitudinal dispersion in ship canals.” J. Hydraul. Res., 24(2), 123–132.
McGuirk, J. J., and Rodi, W. (1978). “A depth-averaged mathematical model for the near field of side discharges into open channel flow.” J. Fluid Mech., 86(4), 761–781.
Park, J. K., and James, A. (1986). “Modeling of pollutant dispersion in stratified oscillatory flows.” J. Environ. Eng., 119(4), 506–524.
Piasecki, M., and Katopodes, N. D. (1999). “Identification of stream dispersion coefficients by adjoint sensitivity method.” J. Hydraul. Eng., 125(7), 714–724.
Rutherford, J. C. (1994). River mixing, Wiley, Chichester, U.K.
Yeremenko, Y. V. (1992). “Determination of the longitudinal dispersion coefficient in a free-surface unsteady flow.” Fluid Mech. Res., 21(3), 131–137.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 134 • Issue 2 • February 2008
Pages: 196 - 204
Copyright
© 2008 ASCE.
History
Received: Jun 14, 2006
Accepted: May 15, 2007
Published online: Feb 1, 2008
Published in print: Feb 2008
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.