Investigating the Discharge Effect on Suspended Sediment Concentration Upstream and Downstream of Obstacles in the Presence of Transverse Waves in Open Channels

The present study has been focused on the formation of transverse waves and the effect of discharge on suspended sediment concentration in the presence of transverse wave based on laboratory tests in a rectangular flume. The results showed that in no transverse wave condition, the concentration of suspended sediment at downstream of obstacles zone was more than that in the absence of obstacles. Transverse waves decreased the transportation of suspended sediment in obstacles zone, so that in the case of existing transverse waves, the concentration of suspended sediment at downstream of obstacles zone was less than that in no obstacles condition. The average values of reduced concentration percentages at downstream of obstacles zone relative to the condition with no obstacles zone, for wave modes 1 and 2 were about 3.6% and 4.5%, respectively. But any significant change was not seen by an increase of dischargefor wave modes 1 and 2. Also the results indicated that an increase of dischargecaused an increase in the maximum amplitude of the wave mode 1, so that the ability of the wave mode 1 for suspended sediment transportation in obstacles zone was increased about 3%, while, it was reduced for the wave mode 2 about 7%. According to the findings, increase of the discharge for the wave mode 2 caused an increase of the transported sediment concentration about 3% in no obstacles condition. But it was decreased for the wave mode 1 and the suspended sediment was deposited at upstream of the obstacles zone. Therefore, the wave mode 2 is more capable of transporting suspended sediment under condition of no obstacles zone than the wave mode 1.