Investigating the Experimental Observations about the Triangular Obstacle Effects at the bottom of reservoir on the Structure of Turbidity Current

Document Type : Research Article

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Abstract

Due to the deposition of density flows in reservoirs, understanding hydrodynamic phenomena governing these flows can have a significant role in their recognition. Use of impermeable obstacles in the course of these currents will be an effective way in increasing the useful life of dams. In this research the effect of the presence of impermeable triangular obstacle on the mechanism of turbidity currents have been investigated experimentally. Velocity of body zone in depth of turbidity current measured by using acoustic doppler velocimeter (ADV) and the concentration profiles are calculated based on ABS method and data distribution. Results show that the obstacle caused an average decrease in velocity of turbidity current head about 35 percent. Waves formed in the vicinity of upstream obstacle are of type A. The formation of a hydraulic jump downstream of obstacle caused changes in the current regime from supercritical to subcritical. Obstacle has led to form new areas of velocity profiles in its upstream part. The presence of obstacle, creates on its upstream a perfect place for settling and trapping sediments. The efficiency of trapping sediment downstream of the obstacle in comparison with the same conditions without obstacle increases about 33 percent.

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References

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History

  • Receive Date: 01 September 2015
  • Revise Date: 27 March 2016
  • Accept Date: 23 May 2016

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