Flow under a sluice gate
Today we are going to demonstrate the flow under a sluice gate using the energy principle. ...
... The theoretical formula based on the conservation of specific energy is:
... in which Q is the discharge, B is the width of the flume, y_{1} is the upstream flow depth, y_{3} is the downstream flow depth, and g is the acceleration of gravity.
For practical purposes, this theoretical formula can be expressed in terms of the gate opening y_{2} by defining a contraction ratio C_{c}:
... This leads to:
... in which the discharge coefficient C_{d} is:
[Point to the width of the flume] The width B of the flume is 6 inches, or 152.4 mm. ... We set the gate opening y_{2} = 15 mm ...
We turn on the pump. ... We set the bed slope equal to zero... and check the level... ... [Point to the point gage] Note that the point gage is at zero at the bottom of the flume. ... Now we are going to measure the upstream flow depth y_{1}. ... The upstream flow depth is y_{1} = X mm
... We move the gage downstream of the sluice gate. ... [Point to the point gage] Note that the point gage is at zero at the bottom of the flume. ... Now we are going to measure the downstream flow depth y_{3}. ... The downstream flow depth is y_{3} = X mm
Applying the theoretical equation based on the conservation of specific energy, the discharge is Q_{1} = X liters per second. ... Next we calculate C_{c} and C_{d}. ... With these coefficients we calculate Q_{2} = X liters per second. ... Note that both equations give the same answer:
