CIV E 530 - OPEN-CHANNEL HYDRAULICS

SPRING 2016 - MIDTERM 2 - SOLUTION

PROBLEM 2

    1. Find the friction factor f:

      f = fD / 8 = 0.032 / 8 = 0.004

      So = f F12

      F12 = So / f = 0.03 / 0.004 = 7.5

      F1 = 2.74   ANSWER.

    2. Find the upstream flow depth:

      F12 = v2/(gy1) = q2/(gy13) = 7.5

      y1 = [q2/(7.5 g)]1/3 = [(2.8)2 /(7.5 × 9.81)]1/3 = 0.474 m.    ANSWER.

    3. Find the downstream flow depth:

      F22 = v2/(gy2) = q2/(gy23) = 1

      y2 = [q2/g]1/3 = [(2.8)2 / 9.81]1/3 = 0.928 m.    ANSWER.

    4. So = Δy/Δx

      Δx = Δy / So = (y2 - y1) / So = (0.928 - 0.474) / 0.004

      Δx = 113.5 m.   ANSWER.

Problem 3

 
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