Publication: Control of sediment entry into an intake canal by using submerged vanes
Date
08-08-2017
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Abstract
River flow which is entering into an intake canal carries lot of sediment due to centrifugal action at river-intake junction and results in various problems. The present work aims to control sediment entry into an intake canal by modifying flow pattern using submerged vanes. Experiments are conducted in a 57.5 cm wide rectangular laboratory model filled with sediment, d50=0.28mm, for a constant discharge of 0.025m3/s and flow depth (H) of 8cm. A rigid bed trapezoidal channel (side slopes, 1H: 1V) of bed width 15 cm, diverting at an angle of 45°from river model is used as an intake channel. Submerged vanes of width 0.18H and 1mm thick are arranged in single and double rows at a spacing (Vs) of 8cm and 12cm. The angle of attack (θ) of vane with respect to flow direction in river model varies as 15°, 300 and 450. A total of seven vanes are arranged as a crest of wave with a central vane height of 0.625 H and decreasing gradually to 0.438H on either side. In single row vane arrangement, for 'Vs'=8 cm and 'θ'=15°, 30°and 450, the sediment entry (S) reduces to 43%, 47% and 57% of sediment entry without vanes (So) and it is 40%, 44% and 48% of 'So' for 'Vs'= 12cm. Further 'S' reduces to 38%, 39% and 47% of 'So', by adding a second row of vanes at a lateral spacing and 'Vs' of 8cm. It is observed that 'S' decreases with an increase of 'Vs' as well as with addition of a second row of vanes and increases with an increase of 'θ'.