Question

Given below are two statements: Statement (I): The Parshall flume consists of three parts, namely, a converging section on the upstream end, a constricted section known as throat and a diverging section on the downstream side. Statement (II): The floor of the converging section is level, the floor of the throat inclines upward and the floor of the diverging section slopes downward. In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Remember the vertical floor profile of a Parshall flume:
Converging = Level; Throat = Slopes Downward; Diverging = Slopes Upward.
This profile accelerates the flow through the throat to establish critical flow.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The Parshall flume is a widely used open-channel flow-metering device developed by Ralph L. Parshall.
It has a specific geometric design that must be constructed precisely to establish critical flow conditions at the throat.

Step 2: Detailed Explanation:
Let us analyze both statements based on the standard geometry of a Parshall flume:
Statement (I): The Parshall flume consists of three distinct horizontal sections: a converging section at the inlet, a constricted throat section in the middle, and a diverging section at the outlet.
This statement is correct.
Statement (II): Let us examine the vertical profile (floor slopes) of each section:
- The floor of the converging section is completely level.
- The floor of the throat section slopes downward to accelerate the water flow and induce critical depth conditions.
- The floor of the diverging section slopes upward to recover head and transition the water back to normal subcritical flow.
Statement (II) states that "the floor of the throat inclines upward and the floor of the diverging section slopes downward," which is the exact opposite of the correct design.
Therefore, Statement (II) is incorrect.

Step 3: Final Answer:
Statement (I) is correct but Statement (II) is incorrect.