Which characteristic is true for uniform flow?

• A. Same depth at every section
• B. Flow can change at different sections
• C. Friction loss is equal length times the slope
• D. Friction slope and channel bottom slope are the same

Answer: (A)

Uniform flow is characterized by a consistent state of flow such that the velocity of the fluid remains constant along a given length of the flow path. This means that not only is the flow velocity constant but also the cross-sectional area, hydraulic radius, and depth of the flow do not change from one section to another over a specific length.

When the flow is uniform, the key feature is that the characteristic depth is the same at every section along the channel, making option A correct. This consistent depth is important, as it demonstrates that the flow's energy level and momentum are also steady throughout that length, contributing to predictability in hydraulic calculations and design parameters in civil engineering applications.

The other characteristics mentioned in the incorrect options contradict the definition of uniform flow. For instance, varying depth or conditions along the flow would indicate non-uniform or varying flow characteristics. Furthermore, the relationship between friction loss, channel slope, and friction slope also relates back to the uniform nature of flow; in uniform flow, these factors align in a specific manner that reflects the steady state of the system, but they do not represent the same principles as a constant depth across the channel.