| saugatshr4 |
March 14, 2022 12:28 |
Outlet BC for multiPhase modeling | Back flow problem
1 Attachment(s)
Hello Foamers,
When I run a multiphase case (air and water), the slow through the domain is satisfactory but when it reaches the outlet there is a problem. The flow starts to comes back and becomes erratic.
I want the flow to move out without any back flow.
I am trying to run a RAS k-epsilon model.
I really hope I can get some help here.
Thank you.
Regards,
Saugat
blockMesh
Code:
convertToMeters 1;
vertices
(
(-135 -600 -105)
(390 -600 -105)
(390 -600 10)//
(-135 -600 10)//
(-135 136 -200)
(390 136 -200)
(390 136 10)//
(-135 136 10)//
);
blocks
(
hex (0 1 5 4 3 2 6 7)(65 85 16)simpleGrading (1 1 1)
);
boundary
(
inlet
{
type patch;
faces
(
(0 1 2 3)
);
}
outlet
{
type patch;
faces
(
(4 5 6 7)
);
}
ground
{
type wall;
faces
(
(0 1 5 4)
);
}
sides
{
type patch;
faces
(
(0 4 7 3)
(1 2 6 5)
(3 7 6 2)
);
}
);
alpha.water
Code:
internalField uniform 0;//initially air in the entire domain - we will change that with setFields!
boundaryField
{
inletwall
{
type zeroGradient;
}
inletwat
{
type fixedValue;
value uniform 1;//only water enters the domain
}
outlet
{
type zeroGradient;
}
ground
{
type zeroGradient;//BC is Neumann BC
}
trySM
{
type zeroGradient;//BC is Neumann BC
}
sides
{
type zeroGradient;//BC is Neumann BC
}
top
{
type zeroGradient;//BC is Neumann BC
}
}
U
Code:
internalField uniform (0 0 0);//Initially the velocity is (0 0 0) m/s
boundaryField
{
inletwat
{
type fixedValue;
value uniform (0 5 0);//fixed inlet velocity
}
inletwall
{
type noSlip;
}
outlet
{
type pressureInletOutletVelocity;
value uniform (0 0 0);
}
ground
{
type noSlip;//no slip along the walls - replaces fixedValue with uniform (0 0 0)
}
trySM
{
type noSlip;//no slip along the walls - replaces fixedValue with uniform (0 0 0)
}
sides
{
type slip;//no slip along the walls - replaces fixedValue with uniform (0 0 0)
}
}
p_rgh
Code:
internalField uniform 0;//initially atmospheric pressure in the entire domain
boundaryField
{
inletwat
{
type fixedFluxPressure;
value uniform 0;
}
inletwall
{
type fixedFluxPressure;
value uniform 0;
}
outlet
{
type fixedValue;
\\p0 uniform 0;
value uniform 0;
}
trySM
{
type fixedFluxPressure;
value uniform 0;
}
ground
{
type fixedFluxPressure;
value uniform 0;
}
sides
{
type slip;
}
}
nut
Code:
internalField uniform 0;
boundaryField
{
trySM
{
type nutkWallFunction;
value uniform 0;
}
inletwall
{
type nutkWallFunction;
value uniform 0;
}
ground
{
type nutkWallFunction;
value uniform 0;
}
".*"
{
type calculated;
value uniform 0;
}
}
k
Code:
internalField uniform 0.0001;
boundaryField
{
inletwat
{
type fixedValue;
intensity 0.05;
value $internalField;
}
inletwall
{
type kqRWallFunction;
value $internalField;
}
outlet
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
trySM
{
type kqRWallFunction;
value $internalField;
}
ground
{
type kqRWallFunction;
value $internalField;
}
sides
{
type slip;
}
}
epsilon
Code:
boundaryField
{
inletwat
{
type fixedValue;
value $internalField;
}
inletwall
{
type epsilonWallFunction;
value $internalField;
}
outlet
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
ground
{
type epsilonWallFunction;
value $internalField;
}
trySM
{
type epsilonWallFunction;
value $internalField;
}
sides
{
type slip;
}
}
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