ANS:B - pressure

In fluid mechanics, when the velocity head (kinetic energy per unit weight of fluid due to its velocity) is converted into another form of energy in a sudden enlargement of a horizontal pipe, it is typically converted into pressure head. Here’s why:

• Velocity Head: Velocity head (V22g\frac{V^2}{2g}2gV2​) represents the kinetic energy per unit weight of fluid due to its velocity (VVV).
• Sudden Enlargement: In a sudden enlargement of a horizontal pipe, such as an abrupt increase in cross-sectional area, the fluid velocity decreases due to the conservation of mass (continuity equation). As the velocity decreases, the kinetic energy associated with the fluid's motion (velocity head) decreases.
• Conversion into Pressure Head: The decrease in velocity (and hence velocity head) in the sudden enlargement results in an increase in pressure in the pipe. This increase in pressure head represents the conversion of the kinetic energy (velocity head) into potential energy in the form of increased pressure.