Question

A compound symmetrical open channel section as shown in the figure has a maximum of \underline{\hspace{2cm} critical depth(s).} \includegraphics[width=1.0\linewidth]{image33.png}

• A. 3
• B. 2
• C. 1
• D. 4

Hint:

In compound open channel sections, the maximum number of critical depths is typically 3 — one for the main channel and two for the floodplain areas.

Answer 1

The Correct Option is A

In a compound open channel section, critical depth is defined as the depth at which the specific energy of flow is minimum for a given discharge. In the case of a compound section, there are generally three possible critical depths: one for the main channel and two for the floodplain channels. This arises because the total discharge can be achieved through multiple combinations of flow in the main and floodplain areas, leading to up to three possible critical depths. Thus, the compound section has a maximum of 3 critical depths.
\[ \boxed{3} \]