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Ali Hamza
Mechanical
04 Feb 2019

# What are different types of flow in open channel flow??

TYPES OF FLOW IN OPEN CHANNELS

Uniform and non-uniform flow

Laminar andTurbulent flow

Subcritical, critical and supercriticalflow

Laminar and Turbulent Flow: For open channels, it is defined with Reynolds No.as;Therefore,

For laminar flow: Re < 500

For Turbulentflow: Re >1000

For transitional flow: 500 < Re <1000

For laminar flow: Re < 2000

For Turbulent flow: Re > 4000

Transitional 2000 < Re < 4000

Where,

Rh = hydraulic radius = A

If width/depth > 10 then R ≅deptℎ

Subcritical, Critical and Supercritical Flow:

These are classified with Froude number.Froude No. (Fr) is ratio of inertial force to gravitational force of flowing fluid.

Mathematically, Froude no.is

Fr. < 1 Flow is subcriticalflow

Fr. = 1 Flow is criticalflow

Fr. > 1 Flow is supercriticalflow

Where, V is average velocity of flow, h is depth of flow and g is gravitational acceleration.