What is the main feature of rapidly varied flow?

• A. Significant changes occur over short distances
• B. Flow is laminar
• C. Pressure remains constant
• D. Velocity is uniform

Answer: (A)

The main feature of rapidly varied flow is that significant changes occur over short distances. This type of flow is characterized by abrupt changes in flow depth, velocity, and other flow parameters, typically due to obstructions or changes in channel geometry. For example, in open channel flow, this can occur at points like weirs, hydraulic jumps, or channel transitions where the flow experiences a sudden change in conditions.

In rapidly varied flow, the physical characteristics of the flow can change dramatically in a very short horizontal distance, making it important to accurately measure and analyze these variations for hydraulic studies and engineering applications.

The other options do not accurately describe this type of flow. Laminar flow, which is smooth and orderly, does not apply to rapidly varied conditions, as the flow is usually turbulent in such scenarios. Pressure variations are common during rapidly varied flow and do not remain constant, while velocity is generally not uniform due to the significant changes occurring over the short spatial length characteristic of this flow condition.