The triangular flume in Fig. 12–22a is used to carry water over a ravine. It is made of wood and has a slope of S_0 = 0.001. If the intended flow is to be Q = 3 m³/s, determine the depth of the flow. Take n = 0.012.
Fluid Description. We assume steady uniform flow of an incompressible fluid.
Analysis. If y is the depth of the flow, Fig. 12–22b, then
P = 2\sqrt{2}y and A = 2[\frac{1}{2}(y)(y)] = y^2
For SI units,
Q = \frac{kA^{5/3}S_0^{1/2}}{nP^{2/3}}; 3 m^3/s = \frac{(1)(y^2)^{5/3}(0.001)^{1/2}}{0.012 (2\sqrt{2} y)^{2/3}}y = 1.36 m