CIV E 530 - OPEN-CHANNEL HYDRAULICS
FALL 2011
LAB No. 9 DEMONSTRATION:  SLUICE GATE

Objective: To demonstrate the principles of the sluice gate using the energy principle.


  1. Theoretical formula based on the conservation of specific energy:

    Q = B y1 y3 [2g / (y1 + y3) ]1/2           [1]

  2. Practical formula based on the gate opening y2:

    Contraction coefficient Cc:

    Cc = y3/y2           [2]

    Cd = Cc / [ 1 + Cc (y2/y1)]1/2           [3]

    Q = B Cd y2 (2g y1)1/2           [4]

  3. With the demonstration flume running, set the gate opening y2 to about 20 mm and measure:

    1. Flume width B

    2. Upstream flow depth y1

    3. Downstream flow depth y3

  4. Calculate:

    1. Discharge Q using Equation 1.

    2. Discharge Q using Equation 4.

  5. Compare discharges calculated in Steps 4a and 4b.

  6. Now set y2 to about 30 mm, measure y1 and y3, and calculate Q using Eqs. 1 and 4.

  7. Write a short report summarizing the findings.