Experimental Study on the Effect of Transverse Waves on Suspended Sediment Concentration at Downstream of Obstacles in a Staggered Arrangement

Document Type : Research Paper

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Abstract

Consequence of the fluid flow passes through a set of obstacles of cylinders, the overlap of shear layers and vortex result in formation of transverse waves. The present study focused on the formation of transverse waves and their effect on suspended sediment concentration based on laboratory tests in a rectangular flume. The results showed that the concentration of suspended sediment at downstream of obstacles zone was equal or more than that at the downstream of no obstacle zone in the no wave condition. Transverse waves decreased the transportation of suspended sediment at the downstream of obstacles zone and the wave mode 1 had the most effect on this phenomenon. According to the findings, for the wave modes 1 and 2 the maximum reductions in the concentration of suspended sediments with an average diameter of 0.12 mm at downstream of obstacles zone in comparison to no obstacles zone were about 12.5% and 8.3% and these reductions for sediment with an average diameter of 0.35 mm were about 8.6% and 3.7%, respectively. Therefore, with the aids of dimensional analysis, dimensionless parameters effects on sediment transportation of each grain size were determined. Finally, by using statical analysis a relationship was proposed to estimate the rate of suspended sediment concentration reduction at obstacles zone in a staggered arrangement for each grain size when transverse wave occured in open channel.

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Water and Soil Science
Volume 26, 2-1 - Serial Number 2
September 2016
Pages 87-100

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