[gusbar]

Hi everybody!


I'm trying to simulate a flow trough an air Knife. At the inlet, the velocity should be approximate 20 m/s. The velocity at the outlet must be constant through the air knife. So I have to simulate various designs to reach this uniform velocity at the outlet.

I tried with different b.c. combinations with simulation model k-omega-sst but my results are not reasonable.
The residuals are oscillating too much and my case is not converging. I give you some information about my settings.
My y+ is about 15 (that's why I set wallFunctions).
I'd be very grateful for any help!!


checkMesh.png residuals.png

fvSchemes
ddtSchemes
{
default steadyState;
}
gradSchemes
{
default cellLimited Gauss linear 1;//faceLimited leastSquares 0.5; //Gauss linear;
//grad(U) cellLimited Gauss linear 1;//
}
divSchemes
{
default none;
div(phi,U) bounded Gauss linearUpwind grad(U);
div(phi,k) bounded Gauss linearUpwind grad(k);//limitedLinear 1;
div(phi,omega) bounded Gauss linearUpwind grad(omega);//limitedLinear 1;
div(div(phi,U)) Gauss linear;
div((nuEff*dev2(T(grad(U))))) Gauss linear;
}
laplacianSchemes
{
default Gauss linear corrected;//limited 0.33;//
}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default corrected;//limited 0.33;//
}
wallDist
{
method meshWave;
}

fvSolutions

p
{
solver GAMG;
tolerance 1e-07;
relTol 0.01;
smoother GaussSeidel;
}

Phi
{
$p;
}

U
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-07;
relTol 0.01;
}

"(k|omega)"
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-06;
relTol 0.01;
}
}
SIMPLE
{
nNonOrthogonalCorrectors 0;
consistent yes;

residualControl
{
p 1e-2;
U 1e-3;
"(k|omega)" 1e-3;
}
}
potentialFlow
{
nNonOrthogonalCorrectors 10;
}

relaxationFactors
fields
{p 0.3;}
equations
{ U 0.7;
k 0.1;
omega 0.1;}

for U I defined:
internalField uniform (0 0 0);
fixedWalls type noSlip;
inlet type fixedValue;
value uniform (20 0 0);
outlet type zeroGradient;


for p : internalField uniform 0;

fixedWalls type zeroGradient;
inlet type zeroGradient;
outlet type fixedValue;
value uniform 0;


for k: internalField uniform 0.84;
inlet type fixedValue;
value uniform 0.84;
outlet type inletOutlet;
inletValue $internalField;
value $internalField;
fixedWalls type kqRWallFunction;
value uniform 0.84;


for omega: uniform 434;
inlet type fixedValue;

outlet type inletOutlet;
inletValue $internalField;
value $internalField;
fixedWalls type omegaWallFunction;
value $internalField;


Greetings
Gustavo