Pick up the incorrect statement with respect to critical flowa)Velocit...
Explanation:
Critical flow is a specific flow condition in open channel hydraulics where the flow velocity reaches the critical velocity. In this condition, the flow is at the maximum possible velocity for a given channel geometry and discharge.
The incorrect statement with respect to critical flow is option C, which states that the specific force is maximum. In critical flow, the specific force is not maximum; it is minimum.
Specific Force:
Specific force is the force exerted on a unit width of a channel by the flowing water. It is given by the equation:
Specific Force = (Flow Velocity)^2 / (Gravity x Hydraulic Depth)
Explanation of Incorrect Statement:
In critical flow, the flow velocity is at its maximum, and the flow conditions are such that the specific force is minimum. This is because at critical flow, the velocity head is equal to the hydraulic depth.
The correct statement regarding the velocity head is option A, which states that the velocity head is equal to half of the hydraulic depth. In critical flow, the velocity head is equal to the hydraulic depth. This means that the kinetic energy of the flowing water is equal to its potential energy.
The correct statement regarding the Froude number is option B, which states that the Froude number is equal to 1. The Froude number is a dimensionless number that represents the ratio of inertial forces to gravitational forces in the flow. In critical flow, the Froude number is exactly 1.
The correct statement regarding the discharge is option D, which states that the discharge is maximum for a given specific energy. In critical flow, the specific energy is at its minimum, and the discharge is maximum for a given specific energy.
Overall, the incorrect statement is option C, which states that the specific force is maximum. In critical flow, the specific force is minimum.
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