[amitshah]

I am unable to figure out why this particular case is not proceeding beyong 3 iterations. Its a simple coarse mesh of a room with hot floor and cold ceiling. The only difference is that there is one cylinder floating inside the domain. Can anyone please tell me whats the obvious mistake here.
Thank you



solvers/heatTransfer> buoyantSimpleFoam . buo-coarse
/*---------------------------------------------------------------------------*\
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: 1.3 |
| \ / A nd | Web: http://www.openfoam.org |
| \/ M anipulation | |
\*---------------------------------------------------------------------------*/

Exec : buoyantSimpleFoam . buo-coarse
Date : Aug 31 2006
Time : 14:59:56
Host : abspc
PID : 30760
Root : /home/abs/OpenFOAM/OpenFOAM-1.3/applications/solvers/heatTransfer
Case : buo-coarse
Nprocs : 1
Create time

Create mesh for time = 0


Reading environmentalProperties
Reading thermophysical properties

Selecting thermodynamics package hThermo<pureMixture<constTransport<specieThermo
<hconstthermo<perfectgas>>>>>
Reading field U

Reading/calculating face flux field phi

Creating turbulence model

Selecting turbulence model kEpsilon
Calculating field g.h

Creating field pd


Starting time loop

Time = 1

BICCG: Solving for Ux, Initial residual = 1, Final residual = 3.3882e-06, No It
erations 5
BICCG: Solving for Uy, Initial residual = 1, Final residual = 6.63001e-06, No I
terations 5
BICCG: Solving for Uz, Initial residual = 1, Final residual = 3.35798e-06, No I
terations 5
BICCG: Solving for h, Initial residual = 1, Final residual = 2.16878e-06, No It
erations 5
ICCG: Solving for pd, Initial residual = 0.456509, Final residual = 9.99191e-09
, No Iterations 89
ICCG: Solving for pd, Initial residual = 0.812018, Final residual = 9.30787e-09
, No Iterations 86
ICCG: Solving for pd, Initial residual = 0.108657, Final residual = 7.95189e-09
, No Iterations 83
time step continuity errors : sum local = 8.56757e-05, global = -1.02539e-15, cu
mulative = -1.02539e-15
rho max/min : 1.18081 0.709729
BICCG: Solving for epsilon, Initial residual = 0.994067, Final residual = 3.412
42e-06, No Iterations 9
BICCG: Solving for k, Initial residual = 1, Final residual = 3.9917e-06, No Ite
rations 7
ExecutionTime = 0.73 s ClockTime = 1 s

Time = 2

BICCG: Solving for Ux, Initial residual = 0.549894, Final residual = 7.5974e-06
, No Iterations 7
BICCG: Solving for Uy, Initial residual = 0.370743, Final residual = 1.20284e-0
6, No Iterations 9
BICCG: Solving for Uz, Initial residual = 0.545532, Final residual = 9.52177e-0
6, No Iterations 8
BICCG: Solving for h, Initial residual = 0.193853, Final residual = 3.16178e-06
, No Iterations 8
ICCG: Solving for pd, Initial residual = 1, Final residual = 7.75263e-09, No It
erations 109
ICCG: Solving for pd, Initial residual = 0.665866, Final residual = 9.61356e-09
, No Iterations 100
ICCG: Solving for pd, Initial residual = 0.0667837, Final residual = 8.25112e-0
9, No Iterations 91
time step continuity errors : sum local = 9.79114e-05, global = -4.33792e-15, cu
mulative = -5.36332e-15
rho max/min : 21600.3 -21718.9
BICCG: Solving for epsilon, Initial residual = 0.861082, Final residual = 4.544
58e-06, No Iterations 7
BICCG: Solving for k, Initial residual = 0.999829, Final residual = 8.53192e-06
, No Iterations 8
ExecutionTime = 1.45 s ClockTime = 2 s

Time = 3

BICCG: Solving for Ux, Initial residual = 0.594618, Final residual = 2.65196e-0
6, No Iterations 6
BICCG: Solving for Uy, Initial residual = 0.3366, Final residual = 3.48334e-06,
No Iterations 6
BICCG: Solving for Uz, Initial residual = 0.513414, Final residual = 3.46801e-0
6, No Iterations 6
BICCG: Solving for h, Initial residual = 0.000359586, Final residual = 1.09077e
-06, No Iterations 3
ICCG: Solving for pd, Initial residual = 0.852691, Final residual = 7.25238e-09
, No Iterations 283
ICCG: Solving for pd, Initial residual = 1.9508e-05, Final residual = 7.86128e-
09, No Iterations 168
ICCG: Solving for pd, Initial residual = 4.41835e-05, Final residual = 6.95792e
-09, No Iterations 109
time step continuity errors : sum local = 1.03926e+08, global = -4.71351e-07, cu
mulative = -4.71351e-07
rho max/min : 8.38268e+15 -3.25762e+17
BICCG: Solving for epsilon, Initial residual = 0.282256, Final residual = 1.124
78e-06, No Iterations 2
bounding epsilon, min: -2.32707e+15 max: 3.23187e+11 average: -1.66999e+12
BICCG: Solving for k, Initial residual = 0.871752, Final residual = 1.83967e-06
, No Iterations 8
bounding k, min: -2.34203e+16 max: 3.79796e+14 average: -2.57615e+13
ExecutionTime = 2.33 s ClockTime = 3 s

Time = 4

BICCG: Solving for Ux, Initial residual = 0.604974, Final residual = 3.06603e-0
6, No Iterations 5
BICCG: Solving for Uy, Initial residual = 0.582094, Final residual = 3.74734e-0
6, No Iterations 5
BICCG: Solving for Uz, Initial residual = 0.32492, Final residual = 2.09804e-06
, No Iterations 5
BICCG: Solving for h, Initial residual = 0.00265806, Final residual = 7.00979e-
06, No Iterations 2


--> FOAM FATAL ERROR : Maximum number of iterations exceeded

From function specieThermo<thermo>::T(scalar f, scalar T0, scalar (specieThe rmo<thermo>::*F)(const scalar) const, scalar (specieThermo<thermo>::*dFdT)(const scalar) const) const
in file /home/dm2/henry/OpenFOAM/OpenFOAM-1.3/src/thermophysicalModels/speci e/lnInclude/specieThermoI.H at line 83.

FOAM aborting

Foam::error::printStack(Foam:stream&)
Foam::error::abort()
Foam::hThermo<foam::puremixture<foam::consttranspo rt<foam::speciethermo<foam::hc > > > > >::calculate()
Foam::hThermo<foam::puremixture<foam::consttranspo rt<foam::speciethermo<foam::hc > > > > >::correct()
buoyantSimpleFoam [0x805cf48]
__libc_start_main
__gxx_personality_v0
Abort

[hjasak]

In the second iteration something has already gone badly wrong: your log file shows negative density.

rho max/min : 21600.3 -21718.9

Also, this is about 5orders of magnitude away from your initial density. My guess is that you've messed up the boundary conditions.

Hrv

[amitshah]

Hi Hrv
Thank you for the earlier reply. I did run a steady state and an unsteady case buoyancy driven flow in a cube 10 cm long with hot (600 K) bottom side and cold (300 K) top side. No velocities were specified. The side walls of the cube were kept at 350 K. I noticed some unique flows in these cases. The transient flow showed one big convection cell centered at the cube center and the steady state showed a different fluid flow than what we see in the hotRoom cases. I can upload them to ou ftp server for you to look at if needed. The mesh is not fine. Can you tell me if it looks right to you?

T
boundaryField
{
floor
{
type fixedValue;
value uniform 600;
}

ceiling
{
type fixedValue;
value uniform 300;
}

fixedWalls
{
type fixedValue;
value uniform 400;
}
}


p
boundaryField
{
floor
{
type wallBuoyantPressure;
}

ceiling
{
type wallBuoyantPressure;
}

fixedWalls
{
type wallBuoyantPressure;
}
}


U
boundaryField
{
floor
{
type fixedValue;
value uniform (0 0 0);
}

ceiling
{
type fixedValue;
value uniform (0 0 0);
}

fixedWalls
{
type fixedValue;
value uniform (0 0 0);
}
}

R
boundaryField
{
floor
{
type zeroGradient;
}

ceiling
{
type zeroGradient;
}

fixedWalls
{
type zeroGradient;
}
}

Hej,

I have a question concerning buoyantSimpleFoam. I would like to modify this solver for my own needs. In my case I don't want to use the Ideal Gas law. I introduced my own function in class equationOfState that returns a density that I need. Also in class basicThermo, hThermo and in the function "calculate" I put my new function instead of psi. And in pEqn.H I replaced psi with my new rho and made corresponding changes.

When I ran my code I got the following erro message:

#0 Foam::error::printStack
#1 Foam::sigSegv::sigSegvHandler
#2 ??
#3
Foam::hThermo<foam::puremixture<foam::consttranspo rt<foam::speciethermo<foam::hc onstthermo<foam::perfectgas>
> > > >::calculate
#4
Foam::hThermo<foam::puremixture<foam::consttranspo rt<foam::speciethermo<foam::hc onstthermo<foam::perfectgas>
> > > >::correct
#5 main
#6 __libc_start_main
#7 Foam::regIOobject::readIfModified
Segmentation fault

It seems that code crushes in the line where I call thermo->correct(). I printed temperature, density - the values are those that I expected.
Could some one give a hint how to fix this problem.

Thank you in advance ,
Rita

[jmmeena]

Mine Solved !