Task 1: Explain the scientific principles in respect of the following giving examples where appropriate. Your work should be referenced using Harvard system and should not exceed 2000 words.
I. Uniform and non-uniform flow
II. Steady and unsteady flow
III. Reynold’s number
IV. Applications of Chezy’s and Manning’s formulae
V. Calculation of river flood Conveyance
VI. Hydraulic jump
VII. Specific Energy
Task 2: A trapezoidal channel has a bed slope of 0.001. The base width is 10 m, the side slopes are 1:3 and the discharge is 30 m3/ sec. Manning’s n can be taken as 0.012.
a) Determine the normal depth of flow, conveyance and Reynold’s Number.
b) What will be the depth if the flow is increased to 45 m3/s?
c) The channel is to be redesigned with a new cross section keeping the same depth but having a discharge of 18m3/s. Propose an appropriate cross section and comment on the new value of conveyance and Reynold’s number
Task 3: A symmetric trapezoidal section, 1600 mm deep and with top and bottom widths 3 m and 0.6 m respectively carries water at a rate of 2.8 m3/sec. Manning’s n may be taken as 0.015. Find:
I. The normal depth at a slope of 1 in 2500
II. The Froude number at the normal depth
Task 4: In a compound channel, the flood channels are 8 m wide and have side slopes of 1:2. The Manning’s n is 0.035 for the banks. The base width and top width for the middle trapezoidal channel is 6 m and 18 m respectively. Manning’s n can be taken as 0.015. If bed slope is 0.001, calculate the Conveyance and Discharge for a flood level of 4m.
Task 5: A river flows along a rectangular channel of width 20 m. The discharge is 75 m3/s and the flow depth is 2m. The width of the channel decreases to 15 m to pass under the bridge. Downstream of the bridge the channel widens smoothly to the original width of 20 m.
a) Determine the depth and flow velocity under the bridge
b) What flow width at the bridge would just cause critical flow?
c) What will happen if this width is decreased further?
Task 6: Water is conveyed at 12 m3/s through a long rectangular channel of width 5m, slope of 0.01% and Manning’s n=0.015. At one point, the channel narrows to a width of 2m. Calculate:
a) The normal depth in the main channel
b) The water depth at the narrow point
Task 7:
a) A broad-crested weir 3.5m wide is to be constructed in a channel to measure a discharge of 4.8m3/s. When the normal depth of flow is 1.2m, calculate the height of weir needed to measure this flow assuming that the flow must go critical on the weir crest.
b) A broad-crested weir is 5.0 m wide and 0.5m high and is used to measure a discharge of 7.5m3/s. Calculate the water depth upstream of the weir assuming that critical depth occurs on the weir and there are no energy losses.
c) A 0.2m step is to be built in a rectangular channel carrying a discharge per unit width of 0.2m3/s. Calculate the effect of this change on the water level in both sub-critical and super-critical flow conditions assuming the specific energy in the upstream channel E1 = 1.0m.
Calculate the effect in the same channel of lowering a section of the channel bed by 0.2m.