Answer Happy

Q1 (a) A broad-crested weir is located in a wide prismatic channel with a bed surface slope of So=2×104 with a discharge per unit width of q=1.5 m³/s per m width. The bed surface roughness has a Manning's coefficient of n is 0.015. Assuming that energy losses may be neglected (and no hydraulic jumps do occur): (i) find the normal and critical flow depths and respective flow energies for this channel flow. [4] (ii) find the height of the weir, so that the flow over the weir will just obtain the critical flow depth. [4] (iii) find the flow depths just upstream the weir (approaching), at the weir, and downstream of the weir, for a weir height of 0.2 m. [6] (iv) find the flow depths just upstream the weir (approaching), at the weir, and downstream of the weir, for a weir height of 0.5 m. [6]