What is rapidly varied flow how it is different from gradually varied flow

Answer 1

Rapidly varied flow is a type of flow in open channels where the depth of the water changes rapidly over a short distance. This can occur in situations such as hydraulic jumps, weirs, and other sudden changes in channel geometry or roughness.

Gradually varied flow, on the other hand, is a type of flow where the depth of the water changes gradually over a long distance. This type of flow is typically seen in natural river channels and is governed by the principles of the Saint-Venant equations.

The main difference between rapidly varied flow and gradually varied flow is the rate at which the depth of the water changes. Rapidly varied flow changes rapidly over a short distance, while gradually varied flow changes gradually over a long distance. Additionally, rapidly varied flow is typically associated with sudden changes in channel geometry or roughness, while gradually varied flow is more commonly seen in natural river channels.