Broad-crested weir: formula for maximum discharge For a broad-crested weir of length L with head H over the crest and coefficient of discharge Cd, select the correct expression for maximum discharge.
Mechanical Engineering
Hydraulics and Fluid Mechanics
Difficulty: Easy
Choose an option
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A0.384 C<sub>d</sub> × L × H<sup>1/2</sup>
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B0.384 C<sub>d</sub> × L × H<sup>3/2</sup>
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C1.71 C<sub>d</sub> × L × H<sup>1/2</sup>
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D1.71 C<sub>d</sub> × L × H<sup>3/2</sup>
Answer
Correct Answer: 1.71 C<sub>d</sub> × L × H<sup>3/2</sup>
Explanation
Concept/Approach
- For free overflow over a broad-crested weir at maximum discharge condition, the theoretical constant is about 1.705; thus Q = 1.71 Cd L H3/2 (SI units when H in metres, Q in m3/s).
Final Answer1.71 Cd × L × H3/2