Critical Flow
Water
When the Froude number is equal to one, the flow is critical and surface waves remain stationary in the flow. Flow at critical depth. Used to describe open channel flow when certain relationships exist between specific energy and discharge, and between specific energy and depth.
A condition of flow where the mean velocity is at one of the critical values; ordinarily at Belanger's critical depth and velocity. Another important usage is in reference to the Reynolds' critical velocities which define the point at which the flow changes from streamline or nonturbulent to turbulent flow.
- — Service Hydrologist Reference Manual Glossary of Hydrologic Terms retrieved 2014-06-01
Weather
In hydrologic terms, a condition of flow where the mean velocity is at one of the critical values; ordinarily at Belanger's critical depth and velocity. Another important usage is in reference to the Reynolds' critical velocities which define the point at which the flow changes from streamline or nonturbulent to turbulent flow.