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Velocity profile is not turbulent (OPEN CHANNEL FLOW)

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Old   August 2, 2016, 15:59
Smile Velocity profile is not turbulent (OPEN CHANNEL FLOW)
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Rui
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Hello Everyone!

I'm simulating flow in a rectangular channel using LES. Depth=0.0975m, Velocity=0.495m/s, Width=0.381m L=10D=0.975m ReL= 96482= D*2*0.495/(10e-06)

Boundary conditions are velocity inlet, Pressure outlet, no-slip wall, symmetry free surface. The yplus of first layer close to the wall is guaranteed to be smaller than 1. Initial conditon, velocity magnitude all over the mesh.

No matter how I change thesetting (Mean velocity, UDF (power law),add some perturbation 10% turbulent intensity) . It still does not look like turbulent velocity profile.

I changed the channel to be more inclined (from 0.01 to 0.03) and changed the setting to be periodic boundary condition. Translational periodic boundary condition is used currently. Specifying the mass flow rate based on the discharge in the channel. 10 flow-through time is used

"
/mesh/modify-zones/make-periodic outlet inlet no yes yes
/define/periodic-conditions/massflow-rate-specification 18.346916 0 0.5 2 0 -0.029986509 -0.9995503
define/boundary-conditions/zone-type watersurface symmetry
"



Still laminar velocity profile

I even add some small square to generate more turbulence at the inlet of the simulation. using periodic boundary condition. Still Laminar velocity profile.

Could you please help me ?
Thank you !

Roi247
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Old   October 5, 2016, 06:52
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muhamed
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Please, do you have a UDF file for inlet velocity profile of an open channel case?
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Old   March 15, 2017, 07:30
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Quote:
Originally Posted by roi247 View Post
Hello Everyone!

I'm simulating flow in a rectangular channel using LES. Depth=0.0975m, Velocity=0.495m/s, Width=0.381m L=10D=0.975m ReL= 96482= D*2*0.495/(10e-06)

Boundary conditions are velocity inlet, Pressure outlet, no-slip wall, symmetry free surface. The yplus of first layer close to the wall is guaranteed to be smaller than 1. Initial conditon, velocity magnitude all over the mesh.

No matter how I change thesetting (Mean velocity, UDF (power law),add some perturbation 10% turbulent intensity) . It still does not look like turbulent velocity profile.

I changed the channel to be more inclined (from 0.01 to 0.03) and changed the setting to be periodic boundary condition. Translational periodic boundary condition is used currently. Specifying the mass flow rate based on the discharge in the channel. 10 flow-through time is used

"
/mesh/modify-zones/make-periodic outlet inlet no yes yes
/define/periodic-conditions/massflow-rate-specification 18.346916 0 0.5 2 0 -0.029986509 -0.9995503
define/boundary-conditions/zone-type watersurface symmetry
"



Still laminar velocity profile

I even add some small square to generate more turbulence at the inlet of the simulation. using periodic boundary condition. Still Laminar velocity profile.

Could you please help me ?
Thank you !

Roi247

Heve you solved your problem? I am facing a very similar situation. If yes, please let me know what you did =).
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