[Akin-iii]

I retrofitted a SimpleFOAM case file for a 2D, Ahmed body (which worked well) and used it for a 3D Ahmed body simulation.

While everything seems okay the force coefficients are completely off the charts.

I checked the velocity and pressure fields and they seem reasonably bounded.

(Max U is 115 m/s for an inlet velocity of 60 m/s)

I'm not sure what I've done wrong.

These are the force coefficient values:

forceCoeffs forceCoeffs write:

Coefficient Total Pressure Viscous Internal

Cd: 266680.75 18136.084 248544.67 0

Cd(f): 328411.84 204044.8 124367.04 0

Cd(r): -61731.086 -185908.72 124177.63 0

Cl: -113975.25 205.29248 -114180.54 0

Cl(f): 57100077 54606743 2493334.7 0

Cl(r): -57214053 -54606537 -2607515.3 0

CmPitch: 57157065 54606640 2550425 0

CmRoll: 195071.46 194976.76 94.702999 0

CmYaw: -1649065 -1635285.9 -13779.085 0

Cs: 9896.5395 5.9612756 9890.5782 0

Cs(f): -1644116.7 -1635282.9 -8833.7963 0

Cs(r): 1654013.2 1635288.8 18724.375 0


I tried attaching the controldict file but it didn't work so here's a snippet of the code for the force coefficients:

functions
{
minMax
{
type fieldMinMax;
libs ("libfieldFunctionObjects.so");
writeControl timeStep; //writeTime;
fields (U);
}
yPlus
{
type yPlus;
libs ("libfieldFunctionObjects.so");
patches (fixedWall);
writeControl writeTime;
}
#includeFunc "writeCellCentres"
#includeFunc "wallShearStress"
forceCoeffs
{
type forceCoeffs;
functionObjectLibs ( "libforces.so" );
outputControl timeStep;
outputInterval 1;

patches
(
ahmedbody
);
pName p;
UName U;

rho rhoInf;
rhoInf 1.225;

CofR (0 0 0);
liftDir (0 1 0);
dragDir (1 0 0);
pitchAxis (0 0 1);
magUInf 60;
lRef 1.044;
Aref 0.112032;
}
#includeFunc "liftcoeff"

functions
{
forces
{
type forces;
functionObjectLibs ("libforces.so");

patches
(
ahmedbody
); // Correct patches
rho rhoInf; // Air density
rhoInf 1.225;
CofR (0 0 0); // Center of rotation

outputControl timeStep;
outputInterval 1;
}
}

Does anyone know what I could be doing wrong?

Cheers!