Effect of Different Bed Configuration on Flow Resistance under Different Flow Regimes in an Open Channel
This study was conducted to evaluate the effect of different bed configuration/bed-forms on flow resistance for different flow conditions in an open channel. The study was limited to investigate whether the flow resistance increases or decreases. The inter-relationship of flow discharge on the friction factor (f) and their quantitative relationship was also determined. A physical model was constructed in the Model Tray Hall of Centre of Excellence in Water Resource Engineering (CEWRE), University of Engineering & Technology Lahore, Pakistan. The sediment commonly available in rivers of Pakistan was used in the channel as bed load under different scenarios. The sediments as bed load were used having the size ranging from 0.5 to 1.2 mm. The bed-forms were predicted using the Athaullah, Simons, Richardson and Van Rijn’s Approach. Darcy–Weisbach equation was used to compute the friction factor (f). The results showed that the friction factor (f) in clear water decreased with increase of discharge upto 18 liter per second and a plane bed type was formed. For flow of 18 to 25 liter per second, a ripple bed type was formed due to increase in friction factor. For flow rate of 25 to 40 liter per second the friction factor decreased and dune bed type was formed.
