CIV E 530 - OPEN-CHANNEL HYDRAULICS
FALL 2013
LAB No. 8:  STEADY GRADUALLY VARIED FLOW II


  1. A horizontal channel of length L = 500 m is designed to convey 5 m3/s from a reservoir to a free overfall. The bottom width is b = 2 m, and side slope z = 1.5. The channel is lined with gabions and the Manning's n recommended by the manufacturer is n = 0.028.

    • What is the headwater depth (accuracy to 1 cm) required to pass the design discharge?

    • What is the tailwater depth, that is, the critical flow depth at the downstream boundary?

    Use ONLINE_WSPROFILES_32; assume m = 100 and n = 100.

  2. A sluice gate is designed to release supercritical flow into a stilling basin, where a hydraulic jump will occur. The basin channel bottom is horizontal, of rectangular cross section. The design discharge is Q = 5 m3/s, the bottom width b = 5 m, and Manning's n = 0.015.

    • What should be the gate opening (accuracy to 1 mm) to ensure that the length of the downstream water surface profile is not greater than 10 m?

    • What is the critical depth?

    Use ONLINE_WSPROFILES_35; assume m = 100 and n = 100. Assume So,u/s = 0.05 so that the flow through the sluice gate remains supercritical.