The 'free flow velocity' under a sharp-edged large orifice (head H, area a) differs from Torricelli''s theorem because:
Choose the correct answer
Torricelli equation works perfectly for large orifices
Head varies over the large orifice opening, so Q is integrated over depth (not a single V=√(2gH))
Large orifice has higher Cd
Velocity is zero for large orifice
Correct Answer
B. Head varies over the large orifice opening, so Q is integrated over depth (not a single V=√(2gH))
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Torricelli: V = √(2gH) (for small orifice, H uniform). For large orifice: head varies from H1 (top) to H2 (bottom), so velocity varies over the opening. Q = ∫Cd×b×√(2gh)dh from H1 to H2 = (2/3)Cd×b×√(2g)×(H2^(3/2)−H1^(3/2)). Large orifice must be integrated (not simply V=√(2gH) at centroid).
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