CIV E 530 - OPEN-CHANNEL HYDRAULICS

FALL 2012 - MIDTERM 2 - SOLUTION

PROBLEM 2

    1. Find the upstream Froude number:

      f = Sc = So  (downstream) = 0.005

      So = Sc F12

      F12 = So / Sc = 0.02 / 0.005 = 4

      F1 = 2   ANSWER.

    2. Find the upstream flow depth:

      F12 = v2/(gy1) = q2/(gy13) = 4

      y1 = [q2/(4 g)]1/3 = [22 /(4 × 9.81)]1/3 = 0.467 m.    ANSWER.

    3. Find the downstream flow depth:

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

      y2 = [q2/g]1/3 = [22 /9.81]1/3 = 0.741 m.    ANSWER.

    4. So = Δy/Δx

      Δx = Δy / So = (y2 - y1) / So = (0.741 - 0.467) / 0.005

      Δx = 54.8 m.   ANSWER.

Problem 3

 
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