Hello folks,
First try using rhoSimpleFoam here. Haven't really done much compressible flow in OpenFOAM before. I have a very simple case of a sphere in a tube. The mesh is about 500k cells and passes all meshCheck just fine.
My BCs are all very simple (trying to keep it that way the first time). I have:
Inlet (U fixed value, T fixed value, zero grad else)
Outlet (p fixed value, zero grad else)
and the walls (walls and sphere) which are all set to 0/zeroGradient.
However, it seems on my first iteration, all of the residuals are nan's and it crashes very quickly:
Time = 1
GAMG: Solving for Ux, Initial residual = nan, Final residual = nan, No Iterations 1000
GAMG: Solving for Uy, Initial residual = nan, Final residual = nan, No Iterations 1000
GAMG: Solving for Uz, Initial residual = nan, Final residual = nan, No Iterations 1000
smoothSolver: Solving for e, Initial residual = nan, Final residual = nan, No Iterations 1000
GAMG: Solving for p, Initial residual = nan, Final residual = nan, No Iterations 1000
time step continuity errors : sum local = nan, global = nan, cumulative = nan
rho max/min : 0.025 0.025
GAMG: Solving for omega, Initial residual = nan, Final residual = nan, No Iterations 1000
GAMG: Solving for k, Initial residual = nan, Final residual = nan, No Iterations 1000
ExecutionTime = 389.481 s ClockTime = 389 s
I can't seem to figure out why. Did I miss something in my BCs?
I set pRefValue manually to be 101325 Pa, so my other BCs and initial condition pressure should be gauge to that.
It says that the rho max/min is 0.025 - but the min and max limiter is 0.5 and 1.5, how did it get that low? This is almost STP...
There is a defaultFaces patch, but this is just left over from blockMesh and has zero faces, so I shouldn't need to worry about it, right?
Here's some of my files:
Code:
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (20 0 0);
boundaryField
{
defaultFaces
{
type fixedValue;
value uniform (0 0 0);
}
inlet
{
type fixedValue;
value uniform (20 0 0);
}
outlet
{
type zeroGradient;
}
wall
{
type fixedValue;
value uniform (0 0 0);
}
sphere
{
type fixedValue;
value uniform (0 0 0);
}
}
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [1 -1 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
defaultFaces
{
type zeroGradient;
}
inlet
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
wall
{
type zeroGradient;
}
sphere
{
type zeroGradient;
}
}
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 0 0 1 0 0 0];
internalField uniform 300;
boundaryField
{
defaultFaces
{
type zeroGradient;
}
inlet
{
type fixedValue;
value uniform 300;
}
outlet
{
type zeroGradient;
}
wall
{
type zeroGradient;
}
sphere
{
type zeroGradient;
}
}
Code:
dimensions [ 0 2 -2 0 0 0 0 ];
internalField uniform 22.815;
boundaryField
{
defaultFaces
{
type compressible::kqRWallFunction;
value uniform 0;
}
inlet
{
type fixedValue;
value uniform 22.815;
}
outlet
{
type fixedValue;
value uniform 22.815;
}
wall
{
type compressible::kqRWallFunction;
value uniform 0;
}
sphere
{
type compressible::kqRWallFunction;
value uniform 0;
}
}
Code:
dimensions [ 0 0 -1 0 0 0 0 ];
internalField uniform 477.26;
boundaryField
{
defaultFaces
{
type compressible::omegaWallFunction;
value uniform 0;
}
inlet
{
type fixedValue;
value uniform 477.76;
}
outlet
{
type fixedValue;
value uniform 477.76;
}
wall
{
type compressible::omegaWallFunction;
value uniform 0;
}
sphere
{
type compressible::omegaWallFunction;
value uniform 0;
}
}
Code:
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
ddtSchemes
{
default steadyState;
}
gradSchemes
{
default Gauss linear;
}
divSchemes
{
default none;
div(phi,U) bounded Gauss linearUpwindV Gauss linear;
div((muEff*dev2(T(grad(U))))) Gauss linear Gauss linear;
div(phi,omega) bounded Gauss linearUpwind Gauss linear;
div(phi,k) bounded Gauss linearUpwind Gauss linear;
div(phi,Ekp) bounded Gauss linearUpwind Gauss linear;
div(phi,e) bounded Gauss linearUpwind Gauss linear;
}
laplacianSchemes
{
default Gauss linear corrected;
}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default corrected;
}
fluxRequired
{
default no;
p ;
}
Code:
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
solvers
{
p
{
solver GAMG;
tolerance 1e-08;
relTol 0.05;
smoother GaussSeidel;
cacheAgglomeration on;
nCellsInCoarsestLevel 20;
agglomerator faceAreaPair;
mergeLevels 1;
}
U
{
solver GAMG;
tolerance 1e-08;
relTol 0.05;
smoother GaussSeidel;
cacheAgglomeration on;
nCellsInCoarsestLevel 20;
agglomerator faceAreaPair;
mergeLevels 1;
}
e
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-06;
relTol 0.1;
}
"(k|omega)"
{
$U;
tolerance 1e-07;
relTol 0.1;
}
}
SIMPLE
{
nNonOrthogonalCorrectors 0;
rhoMin rhoMin [ 1 -3 0 0 0 ] 0.5;
rhoMax rhoMax [ 1 -3 0 0 0 ] 1.5;
pRefPoint (-4.9 0 0);
pRefValue 101325;
residualControl
{
p 1e-2;
U 1e-4;
e 1e-3;
// possibly check turbulence fields
"(k|epsilon|omega)" 1e-3;
}
}
relaxationFactors
{
fields
{
p 0.3;
rho 0.05;
}
equations
{
U 0.7;
"(k|omega)" 0.7;
e 0.5;
}
}
