Flow Over a Rectangular Sharp Weir

Equation (given): Q = (2/3)·Cd·b·√(2g)·H^(3/2). Values: Cd = 0.62 is the discharge coefficient. b = 1.2 m is the crest length, the width of the notch in the front view. H = 0.40 m is the head, measured upstream from the crest level to the water surface, before the surface draws down. g = 9.81 m/s². Step 1: √(2g) = √19.62 = 4.43 m^½/s. Step 2: H^(3/2) = 0.40^1.5 = 0.40 × √0.40 = 0.253 m^(3/2). Step 3: Q = (2/3)(0.62)(1.2)(4.43)(0.253) = 0.556 m³/s. Measuring H at the weir plate, where the surface has dropped, underestimates the flow; using H instead of H^(3/2) gives 0.879 m³/s.