Numerical Investigation of an Estuarine Front and Its Associated Eddy
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 125, Issue 3
Abstract
An estuarine frontal system was investigated with a series of numerical experiments using a 3D hydrodynamic model. The model results were confirmed with field observations and compared with theoretical analysis. Various factors, singly or jointly, contributing to the frontogenesis were investigated. The numerical computations demonstrate that the theoretical critical densimetric Froude number is exceeded as flood current increases and the front is pushed forward to the deeper water. The numerical experiments indicate that two factors contribute significantly to the flow convergence by advancing the phase of flood current on the shoals relative to that in the channel. They are differential friction resulting from depth contrast between deep channel and shoals, and enhanced surface ebb current in the channel resulting from stratification and density induced circulation. Numerical experiments also show that the front is stronger and lasts longer during neap tide than during spring tide. Weaker salinity contrast during spring tide reduces the buoyancy force that is required for the diving of the denser water mass. Furthermore, the stronger flood current during spring tide causes the densimetric Froude number to exceed its critical value earlier, as predicted by the theoretical analysis, and pushes the front away from the region of steep bottom slope, causing it to dissipate.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Blumberg, A. F., and Mellor, G. M. ( 1987). “A description of a three-dimensional coastal ocean circulation model.” Three-dimensional coastal ocean models, coastal and estuarine Sci., N. S. Heaps, ed., Vol. 4, American Geophysical Union, Washington, D.C., 1–19.
2.
Byrne, R. J., et al. ( 1987). “Newport Island: An evaluation of potential impacts on marine resources of the lower James River and Hampton Roads.” Spec. Rep. in Appl. Marine Sci. and Oc. Engrg., No. 283, College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Va.
3.
Clifton, H. E., Phillips, R. L., and Hunter, R. E. ( 1973). “Deposition structures and processes in the mouths of small coastal streams, southwestern Oregon.” Coastal geomorphology, D. R. Coates, ed., State University of New York, Binghamton, N.Y., 115–140.
4.
Dyer, K. R. ( 1973). Estuaries: A physical introduction. Wiley, New York.
5.
Galperin, B., Kantha, L. H., Hassis, S., and Rosati, A. ( 1988). “A quasi-equilibrium turbulent energy model for geophysical flows.” J. Atmospheric Sci., 45, 55–62.
6.
Garvine, R. W. ( 1974). “Physical features of Connecticut River outflow during high discharge.” J. Geophys. Res., 79, 831–846.
7.
Hamrick, J. M. ( 1992a). “Estuarine environmental impact assessment using a three-dimensional circulation and transport model.” Estuarine and Coastal Modeling, Proc., 2nd Int. Conf., M. L. Spaulding et al., eds., ASCE, Reston, Va., 292–303.
8.
Hamrick, J. M. ( 1992b). “Preliminary analysis of mixing and dilution of discharges into the York River.” Rep. to the Amoco Oil Co., College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Va.
9.
Hamrick, J. M. ( 1992c). “Three-dimensional environmental fluid dynamics computer code: Theoretical and computational aspects.” Spec. Rep. in Appl. Marine Sci. and Oc. Engrg., No. 317. College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Va.
10.
Hamrick, J. M. ( 1996). “User's manual for the environmental fluid dynamics computer code.” Spec. Rep. in Appl. Marine Sci. and Oc. Engrg., No. 331. College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Va.
11.
Hamrick, J. M., Kuo, A. Y., and Shen, J. ( 1995). “Mixing and dilution of the Surry nuclear power plant cooling water discharge into the James River.” Rep. to Virginia Power Co., Richmond, College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Va.
12.
Huzzey, L. M. ( 1982). “The dynamics of a bathymetrically arrested estuarine front.” Estuarine, Coast. and Shelf Sci., 15, 537–552.
13.
Ippen, A. T. ( 1966). Estuary and coastline hydrodynamics. McGraw-Hill, New York.
14.
Klemas, V., and Polis, D. F. ( 1977). “A study of density fronts and their effects on coastal pollutants.” Remote Sensing, 6, 95–126.
15.
Kuo, A. Y., Byrne, R. J., Brubaker, J. M., and Posenau, J. H. ( 1988). “Vertical transport across an estuary front.” Physical processes in estuaries, J. Dronkers and W. van Leussen, eds., Springer, Berlin, 93–109.
16.
Kuo, A. Y., Byrne, R. J., Hyer, P. V., Ruzecki, E. P., and Brubaker, J. M. (1990). “Practical application of theory for tidal-intrusion fronts.”J. Wtrwy., Port, Coast., and Oc. Engrg., ASCE, 116(3), 341–361.
17.
Largier, J. L. ( 1986). “Structure and mixing in Palmier Estuary, South Africa.” South African J. Marine Sci., 4, 139–152.
18.
Largier, J. L. ( 1993). “Estuarine fronts: How important are they?” Estuaries, 16(1), 1–11.
19.
Mellor, G. L., and Yamada, T. ( 1982). “Development of a turbulence closure model for geophysical fluid problems.” Rev. Geophys. Space Phys., 20, 851–875.
20.
Moustafa, M. Z., and Hamrick, J. M. ( 1994). “Modeling circulation and salinity transport in the Indian River Lagoon.” Estuarine and Coast. Modeling, Proc., 3rd Int. Conf., M. L. Spaulding et al., eds., ASCE, Reston, Va., 381–395.
21.
Park, K., Kuo, A. Y., Shen, J., and Hamrick, J. M. ( 1995). “A three-dimensional hydrodynamic-eutrophication model (HEM-3D): Description of water quality and sediment process submodels.” Spec. Rep. in Appl. Marine Sci. and Oc. Engrg., No. 327, College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Va.
22.
Sarabun, C. C. ( 1980). “Structure and formation of Delaware Bay fronts.” PhD dissertation, University of Delaware, Newark, Del.
23.
Sarabun, C. C. ( 1993). “Observations of a Chesapeake Bay tidal front.” Estuaries, 16(1), 68–73.
24.
Sharples, J., and Simpson, J. H. ( 1993). “Periodic frontogenesis in a region of freshwater influence.” Estuaries, 16, 74–82.
25.
Shen, J., Sisson, G. M., Kuo, A. Y., Boon, J., and Kim, S. ( 1998). “Three-dimensional numerical modeling of the tidal York River system, Virginia.” Estuarine and Coast. Modeling, Proc., 5th Int. Conf., M. L. Spaulding et al., eds., ASCE, Reston, Va., 495–510.
26.
Simpson, J. H., and Nunes, R. A. ( 1981). “The tidal intrusion front: An estuarine convergence zone.” Estuarine, Coast. and Shelf Sci., 13, 257–266.
27.
Yang, Z. ( 1996). “Variational inverse methods for transport problems.” PhD dissertation, School of Marine Sci., College of William and Mary, Williamsburg, Va.
Information & Authors
Information
Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 125 • Issue 3 • May 1999
Pages: 127 - 135
History
Published online: May 1, 1999
Published in print: May 1999
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.