THE INFLUENCE OF ROUGHNESS ON THE PROPAGATION OF DENSITY CURRENTS

Authors

  • Reza Nasrollahpour Faculty of Civil Engineering, University Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia.
  • Mohamad Hidayat Jamal Faculty of Civil Engineering, University Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia.
  • Zulhilmi Ismail Faculty of Civil Engineering, University Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia.
  • Mehdi Ghomeshi Faculty of Water Sciences Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
  • Peiman Roushenas Faculty of Civil Engineering, University Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia.

DOI:

https://doi.org/10.11113/mjce.v27.15962

Keywords:

Density currents, rough bed, cylindrical roughness, smooth bed, reservoir sedimentation

Abstract

Density currents occur when fluid of one density propagates along a horizontal boundary into fluid of a different density. They are also called turbidity currents when the main driving mechanism is from suspended sediments. Reservoir sedimentation is often related to sediment transport by turbidity currents. The leading edge of a density current is deeper than the following current and is called head or front. In this paper, the effects of bed roughness on density currents propagation were studied. Experiments were carried out over a smooth bed as well as three artificially roughened beds by cylindrical roughness elements. Temporal and spatial evolutions of the current front were analyzed. In experiments performed over rough beds, the measured head velocities were smaller than that of smooth bed. The observed trend is that as the surface roughness increases the front velocity decreases

References

Bombardelli, F. A., Cantero, M. I., Garcia, M. H., and Buscaglia, G. C. (2009). Numerical

Aspects of the Simulation of Discontinuous Saline Underflows: the Lock-exchange

Problem. Journal of Hydraulic Research. 47(6): 777-789.

Cesar, G.D., A. Schleiss and Herman, F. (2001) Impact of Turbidity Currents on Reservoir

Sedimentation. Journal of Hydraulic Engineering. 127(1): 6-16.

Diman, C. P. and Tahir, W. (2012). Dam Flooding Caused a Prolonged Flooding, International

Journal of Civil and Environmental Engineering. 12(6): 71-75.

Fan, J. and Morris, G. L. (1992) Reservoir Sedimentation II: Reservoir Desiltation and Longterm

Storage Capacity. Journal of Hydraulic Engineering. 118(3): 370-384.

Ghomeshi, M. (1995) Reservoir Sedimentation Modelling. PhD Thesis, University of

Wollongong, Australia.

Hacker, J., Linden, P. F. and Dalziel, S. B. (1996) Mixing in lock-release gravity currents.

Dynamics of Atmospheres and Oceans. 24: 183-195.

Kneller, B. and Buckee, C. (2000). The Structure and Fluid Mechanics of Turbidity Currents: A

Review of Recent Studies and Their Geological Implications. Journal of Sedimentology.

(1): 62-94.

Oehy, C., (2003). Effects of obstacles and jets on reservoir sedimentation due to turbidity

currents. Communication 15, A.J. Schleiss, ed., Laboratory of Hydraulic Constructions,

Ecole Polytechnique Fe´de´rale de Lausanne, Lausanne, Switzerland.

Sequeiros, O.E., Spinewine, B., Beaubouef, R.T., Sun, T., Garcia, M.H. and Parker, G. (2010)

Characteristics of velocity and excess density profiles of saline underflows and turbidity

currents flowing over a mobile bed. Journal of Hydraulic Engineering. 136(7): 413-433.

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Published

2018-07-15

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Section

Articles

How to Cite

THE INFLUENCE OF ROUGHNESS ON THE PROPAGATION OF DENSITY CURRENTS. (2018). Malaysian Journal of Civil Engineering, 27. https://doi.org/10.11113/mjce.v27.15962