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High pressure values at inlet and Loss of Mass flow at AMIs -- pimpleDymFoam

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Old   April 14, 2016, 08:04
Angry High pressure values at inlet and Loss of Mass flow at AMIs -- pimpleDymFoam
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Sravan Kumar
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Hi All,

I have been running centrifugal pump steady and transient case in last few months. Steady case works fine with simpleFoam solver. But I have problem with transient case with pimpleDyMFoam.

There is a mass flow loss when fluid is flowing through AMI patches. Also pressure boundary condition is fixed value and zero at outlet, but at inlet the pressure occured is too high. It is almost 5 times more. Inlet boundary condition used is zerogradient.

We have calculated the torque values as well. The torque values agree quite well. But pressure values is the only problem.

I am sharing the case folder for further refence:
https://www.dropbox.com/s/kixdj7oomm...a_135.zip?dl=0

However the case folder cannot be run since I have removed files from polymesh folder. Since I cannot share the geometry details or mesh of the pump. However one have look at the setting I have used.

Please help me out in correcting the errors. Please guide where I have gone wrong .

Also let me know in case you need any further information
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Old   April 15, 2016, 04:41
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Sravan Kumar
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Any help guys
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Old   April 15, 2016, 11:26
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Troy Snyder
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A more appropriate boundary condition (well-posed) for the inflow patch would be totalPressure for p and pressureInletOutltletVelocity for U if you are not specifying the velocity at the inflow.
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Old   April 18, 2016, 02:51
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Sravan Kumar
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Hi Troy,

Thanks a lot for replying.

I have been using following boundary conditions.

For Vel:
Inlet -- fixed value of 5.5
Outlet -- zero gradient

For p:
Inlet -- zero gradient
Outlet -- fixed value of 0

Do u suggest me to use some fixed total pressure at inlet, instead of fixed inlet velocity ?

Please explain if I am not wrong
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