Q1: Hydraulic coefficient of an orifice means the coefficient of

ANS:D - all the above.

1. Coefficient of Velocity: The coefficient of velocity (��Cv​) represents the ratio of the actual velocity of the fluid jet at the vena contracta (the point of maximum velocity downstream from the orifice) to the theoretical velocity of the fluid jet if there were no losses. It is defined as: ��=�actual�theoreticalCv​=vtheoretical​vactual​​ The coefficient of velocity accounts for losses in velocity due to friction, turbulence, and other factors in the flow through the orifice.
2. Coefficient of Contraction: The coefficient of contraction (Cc​) represents the ratio of the area of the vena contracta to the area of the orifice. It is defined as:   Cc​=Aorifice​Avena contracta​​ /  Aorifice  The coefficient of contraction accounts for the reduction in the cross-sectional area of the jet as it passes through the orifice compared to the cross-sectional area of the orifice itself.
3. Coefficient of Resistance: The coefficient of resistance (Cr​) represents the overall resistance to flow through the orifice, including losses due to friction, turbulence, and other factors. It is often used in the context of the hydraulic coefficient of the orifice, which represents the overall resistance to flow. The hydraulic coefficient accounts for both the contraction and velocity effects and is essentially a combination of the coefficient of velocity and the coefficient of contraction.

The hydraulic coefficient of an orifice, often denoted as Cd​ or CO​, is a dimensionless parameter that relates the actual discharge through the orifice to the theoretical discharge that would occur if the orifice were ideal and free from losses. It incorporates both the effects of velocity and contraction, as well as other losses due to friction and turbulence.