Turbulence

Turbulence is the instability generated by shear. Stronger the shear, stronger the turbulence. Lot of factors can give rise to turbulence in a flow.

flow

Laminar flow  to Transition (Chaotic flow) to Turbulent flow

Transition from laminar to turbulent flow typically occurs at the local transition Reynolds number, which varies for different types of flows.

 

Open channel flow

Reynolds number < 500 ( Laminar flow)

Reynolds number > 1000 ( Turbulent flow)

 

Pipe flow

Reynolds number < 2300 ( Laminar flow)

Reynolds number > 4000 ( Turbulent flow)

 

External flow over cylinder/sphere

Reynolds number < 200000 ( Laminar flow)

Reynolds number > 200000 ( Turbulent flow)

 

Flow over flat surface

Reynolds number < 500000 ( Laminar flow)

Reynolds number > 500000 ( Turbulent flow)

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