CIV E 530 - OPEN-CHANNEL HYDRAULICS SPRING 2008 HOMEWORK No. 6 Given the following data for three trapezoidal channels: Channel Q (m3/s) z So n Vmax (m/s) 1 60 2 0.004 0.035 1.5 2 80 2.5 0.002 0.025 1.25 3 75 3 0.0015 0.03 1.0 in which Vmax = maximum permissible velocity. What is the design bottom width (with accuracy to within one-tenth of a meter) required to satisfy the specified maximum permissible velocity? Use ONLINE CHANNEL 01. A channel has the following data:   Q = 300 cfs, z = 2, n = 0.025, and S = 0.002. Use ONLINE TRACTIVE FORCE to calculate the bottom width and depth under the following conditions: The particles are moderately angular and of size d25 = 0.9 in. The particles are of the same size as in (a), but they are moderately rounded. Report the angle of repose θ for cases (a) and (b). Discuss how the particle shape affects the design. A channel has the following data:   Q = 50 m3/s, z = 2, n = 0.03, and S = 0.0004. Use ONLINE TRACTIVE FORCE to calculate the bottom width and depth under the following conditions: The particles on the sides are slightly angular and of size d25 = 25 mm; the particles on the bottom are of size d50 = 5 mm. The particles on the sides are the same as in (a), but the particles on the bottom are smaller, of size d50 = 3 mm. Both cases (a) and (b) have high content of fine sediment in the water and the channel sinuosity is moderate. Discuss how the bottom particle size affects the design.