Civil Engineering MCQJE Level Civil Engineering
According to Lacey's regime theory, the hydraulic mean radius R of a stable alluvial channel is related to the discharge Q as:
Irrigation EngineeringRegime ChannelsHARD
Choose the correct answer
A
R ∝ Q^(1/6)
B
R ∝ Q^(1/3)
C
R ∝ Q^(1/2)
D
R ∝ Q^(2/3)
Correct Answer
B. R ∝ Q^(1/3)
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Lacey's regime formula: R = 0.47 (Q/f)^(1/3), where f is Lacey's silt factor. Thus R ∝ Q^(1/3). Velocity V ∝ Q^(1/6) and area A ∝ Q^(5/6) in Lacey's regime, which differ from Kennedy's approach.
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