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Pressure inlet boundary conditions for open channel flows

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Old   July 10, 2007, 12:41
Default Dear all, I try to use Ope
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JZ
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Dear all,
I try to use OpenFOAM to study discharge capacity problem of a spillway. My problem is schematized as follow figure:

In this 2D problem, the upstream water level, gate opening and downstream water are known. However, the discharge capacity is unknown, so that the inlet velocity can not be given. I setup the inlet and outlet with pressure inlet/outlet boundaries.

But during the simulation, deta_T became smaller and smaller then equal 0! The simulation failed!!

for 1~2 : pressureInlet

gamma = fixedValue=1
velocity=pressureinletVelocity (I used 0)
pd=fixValue (rho*H=constant or 0, both didn't work!)

for 2~3 : pressureInlet
gamma = fixedValue=1
velocity=pressureinletVelocity (I used 0)
pd=fixValue (=0)

for 4~5 pressureOutlet
gamma= zeroGradient
velocity=zeroGradient
pd= fixedValue=0

for 5~6 pressureOutlet

gamma= zeroGradient
velocity=zeroGradient
pd= fixedValue=0


However, I can do the simulation well with velocity inlet BC
for 1~2 : Inlet
gamma = fixedValue=1
velocity=inletVelocity
pd=zeroGradient

for 2~3 : Inlet
gamma=fixedValue =0
velocity=inletVelocity=0
pd = zeroGradient

for 4~5 PresureOutlet

gamma=fixedValue =1
velocity=zeroGradient
pd=zeroGradient

for 5~6 PressureOutlet

gamma=fixedValue=0
velocity=zeroGradient
pd=zeroGradient

It is highly appreciated for any comments or suggestion!

Best Regards!

Jack

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Old   July 10, 2007, 14:36
Default I forgot to mention that I use
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JZ
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I forgot to mention that I used interFoam solver.
Thanks,

Jack
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Old   August 4, 2010, 15:24
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Hello Jack,
I have a similar case. Can you tell me how you solve the problem?
with best regards,
rlobosco
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Old   October 21, 2012, 15:10
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Siamak Gharahjeh
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it seems like it's an outdated post, yet I know the answer, so contact me in case u need.
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Old   October 6, 2016, 09:51
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Christian Fri
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Hi Siamak. What is the answer that you have for this problem?

Thanks!
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Old   December 6, 2018, 12:00
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Akshay Patil
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I am working on a similar problem, would be great if you could share the boundary conditions for U, p_rgh and alpha.water for this particular case. Thank You!
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