CE530- OPEN CHANNEL HYDRAULICS
FALL 2011
SECOND MIDTERM
NOVEMBER 14, 2011, 1600-1715

Name: ________________________ Red ID No. _______________________ Grade: ________

Instructions: Closed book, closed notes. Use engineering paper. When you are finished, staple your work in sequence (1 to 4), and return this sheet with your work.

  1. (30%) A weir is located at the downstream end of a wide rectangular channel of bottom slope So = 0.0025 and dimensionless Chezy friction factor f = 0.0025. The unit-width discharge in the wide rectangular channel is q = 2 m3/s/m. Immediately upstream of the weir, the flow is subcritical, with depth 3.5 m.

    1. Calculate the Froude number of the normal flow in the upstream channel.

    2. Calculate the normal flow depth in the upstream channel.

    3. Calculate the normal flow velocity in the upstream channel.

    4. What is the type of water-surface profile extending from the weir in the upstream direction?

    5. Provide a quick estimate of the length of the water-surface profile.






  2. (30%) A supercritical flow channel with So = 0.016 flows into a critical flow channel of So = 0.004. The boundary friction f is the same is both channels. The unit-width discharge is 2.4 m3/s/m. Find the length of the C3 water surface profile in the critical flow channel.






  3. (40%) Do a tabular comparison between the direct-step and standard-step methods of steady gradually varied flow computation. State eight differences.