Civil Engineering - Hydraulics - Discussion

Ventilation: Ventilation is not required for a triangular notch.

Here are some other facts about triangular notches:

A triangular notch is a sharp crested notch that is used to determine a low rate of flow.
A triangular notch is preferred over a rectangular notch for measuring low discharge.
The bottom edge of a notch over which water flows is known as the sill or crest.
A notch is usually made of a metallic plate.
A 1% error in measuring the height of a triangular notch will produce a 2.5% error in discharge.

I think the ventilation should be necessary. Please explain the given answer.

Option B may be the appropriate answer as we need angle also with H value.

Optn C is correct. Ventilation required only in the rectangular Notch.

Option C is the correct answer.

Please explain the answer.