Study on Undertows Currents in Southern Coasts of Caspian Sea

Document Type : Original Article

Authors

Abstract

   An Undertow is a seaward current that is generated near the sea bed and compensates the shoreward mass transport of sea water. Due to the effective role of this current in sediment transport, this current has been especially considered during recent years.  According to the study of Svendsen and Hansen (1988) [20], research on undertow currents can be carried out based on two views of points. The first view regards the selection a suitable boundary conditions for these current, and the second view considers the determination of the average shear stress of the sea bed. In this paper, the first view has been considered and the characteristics of bed boundary layer, the transportation of the water mass and the undertow velocities have been calculated for some location in shallow water areas of the southern coastline of the Caspian Sea. The results of the investigation show that the onshore-offshore transportation of water mass and undertow velocities decrease from the shore toward the sea. Moreover, the convergence of the calculated data and the field data increases from the shore toward the sea

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References

 
1-     صالح پور، بی تا.، 1382.، انتقال جرم آب عمود بر ساحل در نواحی کم عمق در سواحل جنوبی دریای خزر، پایان نامه کارشناسی ارشد فیزیک دریا، دانشکده علوم دریایی و اقیانوسی خرمشهر، دانشگاه شهید چمران اهواز، 155 صفحه.
2-     پورمندی، امیر حسین.، 1377.، شارش آب و نمک در سواحل جنوبی دریای خزر، پایان نامه کارشناسی ارشد فیزیک دریا، دانشکده علوم دریایی و اقیانوسی خرمشهر، دانشگاه شهید چمران اهواز، 148 صفحه.
3-     چگینی، وحید.، 1377.، مجموعه کتاب‌های مهندسی دریا، چاپ اول، جلد اول، نظریه‌های موج، انتشارات شرکت تحقیقات جهاد آب و آبخیزداری تهران، 301 صفحه.
4-      Bagnold, R. A., 1940. “Beach formation by waves, some model experiments in a wave tank”". J. Inst. Civ. Eng., 15: 27-52.
5-      Bird, E. C. F., 1969. Coasts. M. I. T., Press, Cambridge, Mass., Xiv+246 pp.
6-      Bolanos, R. Thorne, P. D. Wolf, J. (2012). “Comparison of measurements and models of bed stress, bed forms and suspended sediments under combined currents and waves”. Costal Eng., 62:19-30.
7-      Borecki, O. S., 1982. “Distribution of wave-induced momentum fluxes over depth and application within the surf-zone”. Ph. D. Dissertation, Civil Eng., Univ. of Delaware.
8-      Dally, W. R., (1980), “A numerical model for beach profile evolution”. Master thesis, Dept. of Civ. Eng., Univ. of Delaware.                           
9-      Dyhr-Nielsen, M. and Sorensen, T., 1970. “Sand transport phenomena on coasts with bars”. Proc. 12th Costal Eng. Conf., Washington, D. C., Chap. 54, pp. 855-866.
10-  Hansen, J. Buhr and Svendsen, I. A., 1984. “A theoretical and experimental study of undertow”. Proc. 19th Int. Conf. Coastal Eng., Houston, ch. 151, pp. 2246-2262.
11-  Johnson, D. W., 1919. “Shore Processes and Shore Line Development”. Facsimile reproduction 1972, Hafer Publishing Company, New York.
12-  Nadaoka, k., and T. Konoh 1982. “Laboratory measurements of velocity field structure in the surf zone by LDV”. Coast. Eng. Jpn., 25, 125-146.
13-  Nielsen, P., (2009).Coastal and estuarine processes. World Scientific: Advanced Series on Ocean Engineering, 29, p.343.
14-  Soulsby, R. L., (1997). Dynamics of Marine Sands. Thomas Telford, London, UK, p. 249.
15-  Stive, M. J. F. and Wind, H. G., 1986. “Cross-shore means flow in the surf zone”. Coastal Eng., 10:325-340.
16-  Svendsen, I. A, 1984. “Wave heighs and set-up in a surf zone”. Coast. Eng., 8, 303-329.
17-  Svendsen, I. A, 1984. “Mass flux and undertow in a surf zone”. Coastal Eng., 8:347-365.
18-  Svendsen, I. A, 1987. “Analysis of surf zone turbulence”. To appear in J. Geophys. Res.
19-  Svendsen, I. A., Schaffer, H. A. and Buhr Hansen, J., 1987. “The interaction between the undertow and the boundary layer flow on a beach”. J. Geophys. Res., 92 (C11): 11845-11856.
20-  Svendsen, I. B. and Buhr Hansen, J., 1988. “Cross-shore currents in surf- zone modeling”. Coastal Eng., 12:23-42.
21-  Svendsen, I. A., Buhr Hansen and Heming A. Schaffer, 1987. “Analysis of cross-shore circulation on a beach”. Coastal Hydrodynamics, New York pp 508-520.
22-  Van Rijn, Leoc, 1989. “Sediment transport by currents and waves”. Delf Hydraulics, Hand book, Report H 461, Ch. 2, p45.
23-  Van Rijn, Leoc, 1990. “Principal of fluid flow and surface waves in rivers, estuaries, seas, and oceans”. Delf Hydraulics. Ch 8-9 pp. 150-335.
 
 
Nivar
Volume 36, 79-798 - Serial Number 79
September 2012
Pages 45-56

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History

  • Receive Date: 12 February 2016
  • Accept Date: 12 February 2016
  • First Publish Date: 12 February 2016

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