[ljjouc]

Hi, everyone;

I am using OpenFoam 2.2.0.
Now, I have a top boundaryField in my 0/U file and I want to assign a zeroGradient boundary condition for Ux,Uy and a fixedValue for Uz.

This is what I have considered :

top
{
U.component(0)
(
type zeroGradient;
)
U.component(1)
(
type zeroGradient;
)
U.component(2)
(
type fixedValue;
value uniform 0;
)
}
But I am not sure whether it is right? Shall someone can confirm this or tell me the right way to do this?
Thanks in advance for your help.
Kai

[ngj]

Hi Kai,

It looks like a slip boundary. Simply use "type slip;".

Kind regards,

Niels

[ljjouc]

Thanks, Niels. I will try this slip boundary condition.
Best wishes!
Kai

[babakflame]

Dear Foamers

My computational domain is a cylinder containing three distinct inlet boundaries. One of the inlets is a swirl flow. In simple definition, my velocity file is as:

boundaryField
{
    outlet
    {
        type            zeroGradient;
    }
    side
    {
        type            zeroGradient;
    }
    bluffbody
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    inletAir
    {
        type          turbulentInlet;
        referenceField   uniform (0 20 0);
        fluctuationScale (0.02 0.1 0.02);  
    value            uniform (0 20 0);
    }
    inletFuel
    {
        type          turbulentInlet;
        referenceField   uniform (0 32.7 0);
        fluctuationScale (0.04 0.2 0.04);  
    value            uniform (0 32.7 0);
    }
    inletSwirl
    {
        type          swirlFlowRateInletVelocity;
        flowRate         0.0107;
        rpm              6632.42; 
    value            uniform (0 0 0);
    }
}

However, If I use cylindrical inlet boundary for inletSwirl It becomes as:

inlet_swirl
{
type cylindricalInletVelocity;
axis (0 1 0);
centre (0 0 0);
axialVelocity 38.2;
radialVelocity 0;
rpm 6079.9;
value uniform (0 0 0);
}

My question is:
The velocity components in paraview are in cartesian coordinates or cylindrical coordinates by using cylindricalInletVelocity or not using it?


Regards
Bobi