Coefficient of Velocity for a Sharp-Edged Orifice

Coefficient of velocity (Cv) is defined as the ratio of actual velocity of fluid at the vena contracta (the point of minimum area) to the theoretical velocity of fluid at the same point. The value of Cv depends on various factors such as the shape of the orifice, Reynolds number, and the roughness of the orifice surface.

For a sharp-edged orifice, the value of Cv is not constant and can vary widely depending on various factors. Hence, the correct answer is option D, none of these.

Factors Affecting Coefficient of Velocity for a Sharp-Edged Orifice

The value of Cv is affected by various factors such as:

1. Reynolds Number: The value of Cv increases with increasing Reynolds number. At low Reynolds numbers, the flow is laminar and the value of Cv is lower. At high Reynolds numbers, the flow is turbulent and the value of Cv is higher.

2. Shape of the Orifice: The value of Cv depends on the shape of the orifice. For a sharp-edged orifice, the value of Cv is lower compared to a rounded orifice.

3. Roughness of the Orifice Surface: The value of Cv is affected by the roughness of the orifice surface. A rough surface can cause more energy losses and hence the value of Cv is lower.

Conclusion

The coefficient of velocity for a sharp-edged orifice is not constant and can vary widely depending on various factors such as the shape of the orifice, Reynolds number, and the roughness of the orifice surface. Hence, the correct answer is option D, none of these.