What is the term used to describe the depth of uniform flow?

• A. Average depth
• B. Normal depth
• C. Critical depth
• D. Variable depth

Answer: (B)

The term used to describe the depth of uniform flow is "normal depth." This refers to the steady-state condition in open channel flow where the flow velocity, cross-section geometry, and other characteristics are constant over time, resulting in a consistent water surface profile along the channel.

In normal flow, the gravitational forces and frictional forces acting on the water are balanced, which indicates that the flow is neither accelerating nor decelerating. This concept is crucial for engineers when designing channels, as it helps in calculating the channel's hydraulics for predictable flow conditions. In uniform flow, normal depth provides valuable information for determining flow rates and designing appropriate channel dimensions to accommodate expected flows.

The other options do not represent the depth of uniform flow in the same consistent context. Average depth may refer to the mean depth measured over a range of conditions and does not specifically define the steady-state condition. Critical depth is the point at which flow transitions from subcritical to supercritical conditions and indicates the maximum specific energy for a given flow. Variable depth implies changes in water elevation due to various factors, which is contrary to the concept of uniform flow.