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-   -   Pressure inlet boundary conditions for open channel flows (http://www.cfd-online.com/Forums/openfoam-solving/59579-pressure-inlet-boundary-conditions-open-channel-flows.html)

jack2000 July 10, 2007 11:41

Dear all, I try to use Ope
 

Dear all,
I try to use OpenFOAM to study discharge capacity problem of a spillway. My problem is schematized as follow figure:
http://www.cfd-online.com/OpenFOAM_D...ges/1/4875.gif
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


jack2000 July 10, 2007 13:36

I forgot to mention that I use
 
I forgot to mention that I used interFoam solver.
Thanks,

Jack

rlobosco August 4, 2010 14:24

Hello Jack,
I have a similar case. Can you tell me how you solve the problem?
with best regards,
rlobosco

siamakghh2000 October 21, 2012 14:10

it seems like it's an outdated post, yet I know the answer, so contact me in case u need.


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