If the Froude's number (Fr) of flow in open channel is more than 1.0, then the flow is said to be :

Explanation:

Critical flow

It is defined as the flow at which specific energy is minimum or the flow corresponding to critical depth is defined as critical flow.

Relation of critical velocity with critical depth is:

\({V_c} = \sqrt {g \times {h_c}} \)

\(\frac{{{V_c}}}{{\sqrt {g \times {h_c}} }} = Froude\;number = 1\)

Froude number is 1 for critical flow.

Tranquil flow or streaming flow or sub-critical flow

• When the depth of a flow in a channel is greater than critical depth (hc), the flow is said to be sub-critical flow.
• Froude number is less than 1 for sub-critical flow.

Torrential flow or shooting flow or super-critical flow

• When the depth of a flow in a channel is less than critical depth (hc), the flow is said to be a super-critical flow.
• Froude number is greater than 1 for super-critical flow.