Steady, Uniform Flow and where it applies

The steady and uniform flow assumptions provide an essential simplification to understanding the mechanics of flow in rivers.

Learning Goals

Learn about the assumptions of steady and uniform flow and what they mean
Know how to compute a backwater length and that this is the zone in which the steady, uniform flow assumption does not apply

Steady, uniform flow computer-graphics illustration

The robot voice may be strange, but it is right!

Video lecture

Here I discuss steady flow, uniform flow, and how to tell when a backwater effect may be present.

Note that we consider the question of steady, uniform flow purely in the downsteram direction. Natural flows do vary across the channel.

Unsteady and nonuniform flow example: dam-breach experiment

Steady, uniform flow examples

Slow-moving river

You don’t have to watch all 3 hours!

Mountain stream

When averaged over short periods of time, such that the turbulent cascade averages out, flow in this river (believe it or not!) is also steady and uniform.