In orifice hydraulics, the term “hydraulic coefficients” commonly refers to which coefficient(s)?

Introduction / Context:
Real orifice jets deviate from ideal theory due to contraction and energy loss. Engineers therefore use empirical coefficients to relate actual to theoretical values, collectively termed the hydraulic coefficients of an orifice.

Given Data / Assumptions:

• Sharp-edged orifice, steady flow.
• Coefficients treated approximately constant over small head ranges.

Concept / Approach:

Key coefficients are: coefficient of contraction Cc (area reduction to vena contracta), coefficient of velocity Cv (actual jet speed/theoretical), and coefficient of discharge Cd = Cc * Cv (actual discharge/theoretical). Sometimes a “coefficient of resistance” is discussed via head loss relations, but standard trio remains Cc, Cv, and Cd—together called hydraulic coefficients.

Step-by-Step Solution:

Verification / Alternative check:

Laboratory calibration of an orifice plate gives Cd close to 0.6 for sharp-edged small orifices in water, consistent with typical Cc ≈ 0.62 and Cv ≈ 0.97.

Why Other Options Are Wrong:

(a), (b), and (c) each name part of the set; the most complete answer is (d) “All of the above.” (e) is false.

Common Pitfalls:

Using Cd alone without understanding its decomposition; assuming coefficients are constants across all heads and Reynolds numbers.

Final Answer:

All of the above