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Outlet problem

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Old   March 3, 2020, 15:26
Default Outlet problem
  #1
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Joe
Join Date: Oct 2016
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Hi everyone.


Im running a 2D multiphase (interFoam) case of a dam spillway (k-e turbulence model). The results at the outlet patch is not correct. Attached the result. Water is entering from the left. The inlet is from the bottom patch left of the ogee spillway. Water flows to the right and shoots up the sk-jump. The outlet is the right hand side vertical patch as well as the 45 degrees corner patch. Below some of the BC's.


The water is supposed to just flow out of the domain and not shoot vertically upwards. Gravitational acc. is in the -x direction.


Does someone know what am I doing wrong?



alpha.water:


inlet
{
type fixedValue;
value uniform 1;
}

outlet
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;

}

atm
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}

symm
{
type symmetryPlane;
}

floor
{
type zeroGradient;
}

bottomEmptyFaces
{
type empty;
}

topEmptyFaces
{
type empty;
}


p_rgh:

inlet
{

type zeroGradient;

}

outlet
{

type totalPressure;
p0 uniform 0;
}

atm
{
type totalPressure;
p0 uniform 0;

}

floor
{
type fixedFluxPressure;
value uniform 0;
}

symm
{
type symmetryPlane;
}

bottomEmptyFaces
{
type empty;
}

topEmptyFaces
{
type empty;
}


U:



inlet
{
type fixedValue;
value uniform (0.427 0 0);
}

outlet
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}

atm
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}

floor
{
type noSlip;
}

symm
{
type symmetryPlane;
}


bottomEmptyFaces
{
type empty;
}

topEmptyFaces
{
type empty;
}
Attached Images
File Type: jpg spillway.jpg (20.5 KB, 8 views)
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Old   March 3, 2020, 16:10
Default
  #2
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Akash Patel
Join Date: Dec 2018
Location: Champaign, IL, USA
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Quote:
Originally Posted by OOTB View Post






U:



inlet
{
type fixedValue;
value uniform (0.427 0 0);
}

outlet
{
type inletOutlet;
inletValue uniform (0 0 0);
value $internalField;
}


atm
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}

floor
{
type noSlip;
}

symm
{
type symmetryPlane;
}


bottomEmptyFaces
{
type empty;
}

topEmptyFaces
{
type empty;
}

Try making this change in velocity initial field. Instead of setting outlet value to zero, you should be using internalField value solved at each timestep. Similarly change value of inletOutlet BC in other fields as well.
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Old   March 4, 2020, 12:17
Default Outlet Problem
  #3
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Joe
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Thank you Akash!

That worked.. but I had to change the bc for p_rgh at the outlet to zeroGradient.

Thank you for your time it helped me alot.
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