CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

buoyantSimpleFoam and watertank

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree25Likes

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 29, 2013, 16:05
Default buoyantSimpleFoam and watertank
  #1
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Dear Foamers,

I am working (since 2 weeks) on a very simple simulation.

What I want to simulate:

Something like that: http://www.wiga-energietechnik.de/bi...mage/lwsp2.gif


What I did:

- I meshed the whole geometry with a corse and very fine mesh
- I build polynoms for water thermodynamics (30°C-70°C)
- I changed the thermodynamics for water
- Simulation is LAMINAR

- Inlet 4e-5 m³/s

- At the inlet I have a very simple pipe installation but the solver blow up every time so I just set an Inlet + Outlet (thats all - see pictures).

Now my problem:

Every BC I set make problems.

I am not 100% sure how I should set the p_rgh BC for inlet/outlet/wall.

p is calculated.


For U and T its clear.

The solver is working just for 1 or none iterations.
If I set of the gravity the simulation is working.

It seems that the solver is calculating my water with a compressibility because after the first time step I get extrem huge velocity fields in the big domain.


I tried a lot of BC for U + p_rgh - fixed at the outlet - pressureInletOutletVelocty etc.

Does someone can give me a hint how to set these BC right?

Relaxationfactors are decreased to 0.1.
linearUpwind + limitedLinear schemes are used etc...


Interesting fact:

without gravitation the simulation is working.
With gravitation the mass flux cant be calculated:
Code:
--> FOAM FATAL ERROR: 
Continuity error cannot be removed by adjusting the outflow.
Please check the velocity boundary conditions and/or run potentialFoam to initialise the outflow.
Total flux              : 102320
Specified mass inflow   : 0.29563
Specified mass outflow  : 0.151702
Adjustable mass outflow : 0
For gravity I have to set the outlet p_rgh to fixedValue that I can calculate the first timestep but after that the solver blow up again. A picture of p, p_rgh and U is included in the attachment.

The error message:
Code:
Time = 2

DILUPBiCG:  Solving for Ux, Initial residual = 0.733571, Final residual = 0.0031127, No Iterations 7
DILUPBiCG:  Solving for Uy, Initial residual = 0.623405, Final residual = 0.000739902, No Iterations 8
DILUPBiCG:  Solving for Uz, Initial residual = 0.701814, Final residual = 0.0023944, No Iterations 7
DILUPBiCG:  Solving for h, Initial residual = 1, Final residual = 0.00132406, No Iterations 2


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

    From function thermo<Thermo, Type>::T(scalar f, scalar T0, scalar (thermo<Thermo, Type>::*F)(const scalar) const, scalar (thermo<Thermo, Type>::*dFdT)(const scalar) const, scalar (thermo<Thermo, Type>::*limit)(const scalar) const) const
    in file /home/shorty/OpenFOAM/OpenFOAM-2.2.x/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 76.

FOAM aborting
Compared with the velocity field its clear why its blow up but I can not fix it.


Any suggestions would be appreciated.

Regards Tobi
Attached Images
File Type: jpg picture.jpg (12.9 KB, 334 views)
File Type: jpg P.jpg (16.4 KB, 322 views)
File Type: jpg U.jpg (12.9 KB, 280 views)
Tobi is offline   Reply With Quote

Old   October 30, 2013, 02:55
Default
  #2
Member
 
hannes
Join Date: Mar 2013
Posts: 47
Rep Power: 13
hanness is on a distinguished road
Hi Tobi,

seems to me as your problem might arise due to the initial conditions of p. In your final solution the p field should be close to the hydrostatic field and p_rgh close to constant. However, if you assume p to be constant in the beginning then you get the p_rgh field shown in your plot which leads to high velocities and possibly even to a crash. The problem is that in the very first step the solver uses the p-field to calculate the p_rgh field although your boundary conditions are set for p_rgh and p is set to calculated. So what you can do is either adapt the solver (which is just a change of one line) or probably a little bit easier use funkySetFields to set the initial pressure field to the hydrostatic pressure.

Hope that helps
Hannes
hanness is offline   Reply With Quote

Old   October 30, 2013, 04:41
Default
  #3
Senior Member
 
Tom Fahner
Join Date: Mar 2009
Location: Breda, Netherlands
Posts: 646
Rep Power: 32
tomf will become famous soon enoughtomf will become famous soon enough
Send a message via MSN to tomf Send a message via Skype™ to tomf
Hi Tobi,

As a by-pass you could run initially with gravity turned off. Than after say 200 iterations turn gravity on. Unfortunately it is not run-time modifiable so you have to stop (and save) the run, change gravity and rerun from latestTime.

Regards,
Tom
tomf is offline   Reply With Quote

Old   October 31, 2013, 04:24
Default
  #4
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi,

thanks for your replays.


I tried Toms hints.
The pictures show p, p_rgh and U after 500 iterations.

Then i turned gravity on and the 501 step is shown in the 2nd replay.

@hannes: what lines had to be modified?
@all: could it be possible that my polynomes are wrong?
Attached Images
File Type: jpg p.jpg (14.4 KB, 196 views)
File Type: jpg p_rgh.jpg (14.6 KB, 192 views)
File Type: jpg U.jpg (16.0 KB, 218 views)

Last edited by Tobi; October 31, 2013 at 07:41.
Tobi is offline   Reply With Quote

Old   October 31, 2013, 04:49
Default
  #5
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Here are the pictures at 501 iterations.
After that my solver blow up:
Code:
[5] 
[5] 
[5] --> FOAM FATAL ERROR: 
[5] Maximum number of iterations exceeded
[5] 
[5]     From function thermo<Thermo, Type>::T(scalar f, scalar T0, scalar (thermo<Thermo, Type>::*F)(const scalar) const, scalar (thermo<Thermo, Type>::*dFdT)(const scalar) const, scalar (thermo<Thermo, Type>::*limit)(const scalar) const) const
[5]     in file /home/shorty/OpenFOAM/OpenFOAM-2.2.x/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 76.
[5] 
FOAM parallel run aborting
[5] 
[5] #0  Foam::error::printStack(Foam::Ostream&) in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
[5] #1  Foam::error::abort() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
[5] #2  Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::T(double, double, double, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double, double) const, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double, double) const, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double) const) const in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
[5] #3  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::polynomialTransport<Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>, 8> > >::calculate() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
[5] #4  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::polynomialTransport<Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>, 8> > >::correct() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
[5] #5  
[5]  in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/bin/buoyantSimpleFoam"
[5] #6  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[5] #7  
[5]  in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/bin/buoyantSimpleFoam"
One hint for p_rgh:

Code:
  p0 = p_rgh + rho*gh
Normally I should have such a pressure field shown in the picture, am I not?
Because my tank is 2m high and the fluid is water (1000kg/m³).

So as I see in this formula the higher I get in the tank the lower p0 should be because:

Code:
rho ~ 1000kg/m³
g = -9,81
h raises

p0 = p_rgh - 1000* 9,81 * 2
Is that correct?
Therefor p and p_rgh should not be the same?
Attached Images
File Type: jpg p_501.jpg (16.3 KB, 111 views)
File Type: jpg p_rgh_501.jpg (16.9 KB, 104 views)
File Type: jpg U_501.jpg (19.9 KB, 119 views)
Tobi is offline   Reply With Quote

Old   October 31, 2013, 05:08
Default
  #6
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi all,

just one question. Why is in interFoam the p0 calculation for nonclosedVolumes like that:
Code:
p == p_rgh + rho*gh;
and in buoyant***Foam like that:
Code:
p = p_rgh + rho*gh;
Regards
Tobi
Tobi is offline   Reply With Quote

Old   October 31, 2013, 13:56
Default
  #7
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi all,

I made a test with chtMultiRegionSimpleFoam with only one region.
Just a very simple case - box with inlet and outlet at the top of the box.

If I use the thermodynamics out of the liquidHeater tutorial:
Code:
thermoType
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState rhoConst;
    specie          specie;
    energy          sensibleEnthalpy;
}

mixture
{
    specie
    {
        nMoles          1;
        molWeight       18;
    }
    equationOfState
    {
        rho             1000;
    }
    thermodynamics
    {
        Cp              4181;
        Hf              0;
    }
    transport
    {
        mu              959e-6;
        Pr              6.62;
    }
}
Its working.
After switching to my own thermodynamic with the polynoms its blow up after the 4th iteration:
Code:
thermoType
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       polynomial;
    thermo          hPolynomial;
    equationOfState icoPolynomial;
    specie          specie;
    energy          sensibleEnthalpy;
}

mixture
{
    specie
    {
        nMoles          1;
        molWeight       18;
    }

    equationOfState
    {
          rhoCoeffs<8>  (611.705 2.78 -0.005 5.58512e-13 -4.3231e-16 0 0 0);
    }

    thermodynamics
    {
        Hf              0;
        Sf              0;
        CpCoeffs<8>     (5158.69 -6.26 0.01 6.17887e-12 -4.78243e-15 0 0 0);
    }

    transport
    {
        muCoeffs<8>     (0.000292721 -3.33273e-6 1.43625e-8 -2.76923e-11 2.0125e-14 0 0 0);
        kappaCoeffs<8>  (-55.2758 0.683843 -0.00315152 6.47667e-6 -5e-9 0 0 0);
    }
}

Therefor I made a test just with the first coefficient like:
Code:
rhoCoeffs<8>   (1000 0 0 0 0 0 0 0);
for all other polynoms too. But the result is the same - after 3 iterations the solver blow up due to maximum Iteration reached:

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

    From function thermo<Thermo, Type>::T(scalar f, scalar T0, scalar (thermo<Thermo, Type>::*F)(const scalar) const, scalar (thermo<Thermo, Type>::*dFdT)(const scalar) const, scalar (thermo<Thermo, Type>::*limit)(const scalar) const) const
    in file /home/shorty/OpenFOAM/OpenFOAM-2.2.x/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 76.

FOAM aborting

#0  Foam::error::printStack(Foam::Ostream&) in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#1  Foam::error::abort() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#2  Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::T(double, double, double, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double, double) const, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double, double) const, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double) const) const in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
#3  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::polynomialTransport<Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>, 8> > >::calculate() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
#4  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::polynomialTransport<Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>, 8> > >::correct() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
#5  
 in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/bin/chtMultiRegionSimpleFoam"
#6  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#7  
 in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/bin/chtMultiRegionSimpleFoam"
Abgebrochen (Speicherabzug geschrieben)
Any hints?
I am out of mind and have no further ideas at the moment.

Regards
Tobi
2538sukham likes this.
Tobi is offline   Reply With Quote

Old   October 31, 2013, 14:12
Default
  #8
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi all,

just notice:

I am stupid!


All values of mu are wrong. Instead of writing:

503,89e-6

I wrote

0,50389e-6


After changing this, the easy test case is working. Now I am going to check if my bigger project is working too.
Tobi is offline   Reply With Quote

Old   October 31, 2013, 16:10
Default
  #9
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Okay.

I checked it out with the other case.
Without gravity its working (bouyantSimpleFoam and chtMultiRegionSimpleFoam).

But after switching on the gravity its still the same.

Regards Tobi
Tobi is offline   Reply With Quote

Old   October 31, 2013, 20:28
Default
  #10
Senior Member
 
Joachim Herb
Join Date: Sep 2010
Posts: 650
Rep Power: 22
jherb is on a distinguished road
Perhaps your problem is the same as described in this thread:
http://www.cfd-online.com/Forums/ope...roperties.html

You could also try the transient solver (buoyantPimpleFoam)
jherb is offline   Reply With Quote

Old   November 4, 2013, 04:03
Default
  #11
Member
 
hannes
Join Date: Mar 2013
Posts: 47
Rep Power: 13
hanness is on a distinguished road
Dear Tobi,

the pictures you showed match exactly the problem we had. I'm pretty sure that your results will improve when you start the simulations with hydrostatic pressure distribution for p. What happens is when you turn on gravity the pressure field rapidly changes in order to be consistent so that's why you get those strong gradients in the p_rgh field which again results in the high velocities.
If you don't want to set your p field with funkySetFields then you should adapt your solver. Copy the solver and the only thing you have to change in createFields.H is the line reading
Code:
p_rgh = p - rho*gh;
For the buoyantSimpleFoam solver it is line 71
Replace it by solving for p:
Code:
p = p_rgh + rho*gh
This way you initialise using the constant p_rgh field instead of the constant p field which is much closer to the real solution.

Regards
Hannes
jherb, Tobi, student666 and 4 others like this.
hanness is offline   Reply With Quote

Old   November 4, 2013, 06:43
Default
  #12
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi all,

thanks for the hints but it is still not working.
On my easy case the chtMultiRegionSimpleFoam solver (only with one domain) is working. But the buoyantSimpleFoam is not working. Additionally I tryed the hints hannes said but not with success.


In the attachment you find a picture of the chtMultiSImpleFoam solver and the solution.
I have no further idea at the moment.

For me it seems that the buoyantSimpleFoam is not a good solver for the thing I want to do. Furthermore the chtMultiSimpleFoam solver is not working in my big case too.

Thanks for your help but I think I have to give up on that project.
Maybe "WATER" is not very common for the solvers.

At least I had a look into the cht solver and the createFields.H file.
There is the same calculation as in the buoyantSimpleFoam.
So I have no idea why this solver is working and the other one not :/




Regards Tobi
Attached Images
File Type: jpg chtMulti.jpg (17.6 KB, 174 views)
Tobi is offline   Reply With Quote

Old   November 4, 2013, 07:26
Default
  #13
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi all,

now the pressure fields are the same (buoyantSimpleFoam and chtMultiRegionSimpleFoam) .

I had to change the schemes to get the same results


Now I am going to check if its working wit a bigger domain.
Tobi is offline   Reply With Quote

Old   November 4, 2013, 08:50
Default
  #14
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Summary with a bigger domain:


- chtMultiRegionSimpleFoam isn 't working anymore
- buoyantSimpleFoam isn 't working anymore
- myBuoyantSimpleFoam with the modification in the createFields.H is working.

Hannes I think the work is done now.
I will check my official geometry now.

I keep you posted.
Tobi is offline   Reply With Quote

Old   November 4, 2013, 09:26
Default
  #15
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Quote:
Originally Posted by hanness View Post
Dear Tobi,

the pictures you showed match exactly the problem we had. I'm pretty sure that your results will improve when you start the simulations with hydrostatic pressure distribution for p. What happens is when you turn on gravity the pressure field rapidly changes in order to be consistent so that's why you get those strong gradients in the p_rgh field which again results in the high velocities.
If you don't want to set your p field with funkySetFields then you should adapt your solver. Copy the solver and the only thing you have to change in createFields.H is the line reading
Code:
p_rgh = p - rho*gh;
For the buoyantSimpleFoam solver it is line 71
Replace it by solving for p:
Code:
p = p_rgh + rho*gh
This way you initialise using the constant p_rgh field instead of the constant p field which is much closer to the real solution.

Regards
Hannes
Hi Hannes - your hint is working fine
Thanks a lot.


Just one question to that.
Why isn 't it implemented as you wrote?

I think there is any reason for that?

Additionally with the PIMPLE algorithm it is not working.
Do you have any experience with that?

Maybe I will initialize it with simple and then switch to pimple.

Regards Tobi
jmonsa13 likes this.

Last edited by Tobi; November 4, 2013 at 10:35.
Tobi is offline   Reply With Quote

Old   November 5, 2013, 12:25
Default
  #16
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi all,

with the modified buoyantSimpleFoam solver my case is working and the steady state result is very nice.

After initialize this solution with the buoyantPimpleFoam solver I get crazy p_rgh and p fields again
Tobi is offline   Reply With Quote

Old   November 6, 2013, 09:53
Default
  #17
Member
 
hannes
Join Date: Mar 2013
Posts: 47
Rep Power: 13
hanness is on a distinguished road
Hi Tobi,

I can't really tell you why it is implemented that way, I'm not aware of any restrictions at that point. Maybe the thinking is, that it is easier to initialise a pressure field which is a little more intuitiv then to initialise p_rgh when not starting with constant fields.
However, concerning the problem with buoyantPimpleFoam I could only guess. First of all, one thing that might become neccessary is to increase your writePrecision in controlDict, the standard six (or eight?) digits are by far not sufficient when small fluctuations in p_rgh are concerned, so that might be a reason why a restart might fail. Otherwise it should be possible to run the simulation with the buoyantPimpleFoam starting from a constant field when the same change to the solver is performed (change in createFields.H).
Could you provide some more information on the crash if the above does not help?

Hannes
chathuranga likes this.
hanness is offline   Reply With Quote

Old   November 6, 2013, 11:03
Default
  #18
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Dear Hannes,

thanks for your replay.

I also tried to start the simulation with the change in the createField.H.
But without success.

Additionally I changed the time precision like you said but the same - crash.
Here is the output:

Code:
Starting time loop

Courant Number mean: 6.92740210013e-09 max: 4.85034908134e-06
deltaT = 1.199999616e-07
Time = 1.2e-07

diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG:  Solving for Ux, Initial residual = 2.28465064941e-09, Final residual = 2.28465064941e-09, No Iterations 0
DILUPBiCG:  Solving for Uy, Initial residual = 2.43944451461e-09, Final residual = 2.43944451461e-09, No Iterations 0
DILUPBiCG:  Solving for Uz, Initial residual = 1.09072719922e-09, Final residual = 1.09072719922e-09, No Iterations 0
DILUPBiCG:  Solving for h, Initial residual = 3.35094034737e-06, Final residual = 2.93432135474e-18, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.999966166727, Final residual = 4.61953060743e-07, No Iterations 25
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.21330773016e-17, global = 3.97805509428e-17, cumulative = 3.97805509428e-17
ExecutionTime = 42.62 s  ClockTime = 60 s

Courant Number mean: 8.31290630685e-09 max: 5.82512408095e-06
deltaT = 1.43999933184e-07
Time = 2.64e-07

diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG:  Solving for Ux, Initial residual = 0.000359951353176, Final residual = 2.99850393754e-17, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.000406515147044, Final residual = 4.7022285039e-17, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 5.62159242983e-05, Final residual = 3.53128489406e-18, No Iterations 1
DILUPBiCG:  Solving for h, Initial residual = 0.000118849971877, Final residual = 8.30419637485e-17, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.503136149457, Final residual = 2.61630245853e-07, No Iterations 26
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 3.97094383529e-17, global = 1.86616925674e-17, cumulative = 5.84422435102e-17
ExecutionTime = 66.02 s  ClockTime = 89 s

Courant Number mean: 9.97543173077e-09 max: 6.99668194517e-06
deltaT = 1.72799880008e-07
Time = 4.368e-07

diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG:  Solving for Ux, Initial residual = 0.00020724814406, Final residual = 5.63890977966e-17, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.000235776423607, Final residual = 4.17515596363e-17, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 3.23259354164e-05, Final residual = 1.41492437006e-17, No Iterations 1
DILUPBiCG:  Solving for h, Initial residual = 0.999999131419, Final residual = 1.4011399717e-14, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.999982729227, Final residual = 9.81585468245e-07, No Iterations 52
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.90312676653e-13, global = -1.04003980939e-14, cumulative = -1.03419558504e-14
ExecutionTime = 100.86 s  ClockTime = 130 s

Courant Number mean: 0.00016710031461 max: 0.221478550247
deltaT = 3.90105209282e-08
Time = 4.7581e-07

diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG:  Solving for Ux, Initial residual = 0.0892826131216, Final residual = 3.47960960238e-10, No Iterations 2
DILUPBiCG:  Solving for Uy, Initial residual = 0.0860767448894, Final residual = 2.07507793124e-10, No Iterations 2
DILUPBiCG:  Solving for Uz, Initial residual = 0.00526497170747, Final residual = 5.00604327108e-07, No Iterations 1
DILUPBiCG:  Solving for h, Initial residual = 0.999999999974, Final residual = 1.22827994334e-07, No Iterations 1
#0  Foam::error::printStack(Foam::Ostream&) in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#1  Foam::sigFpe::sigHandler(int) in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#2   in "/lib/x86_64-linux-gnu/libc.so.6"
#3  Foam::GAMGSolver::scale(Foam::Field<double>&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::Field<double> const&, unsigned char) const in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#4  Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMatrix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#5  Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#6  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfiniteVolume.so"
#7  Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/home/shorty/OpenFOAM/shorty-2.2.x/platforms/linux64Gcc47DPOpt/bin/myBuoyantPimpleFoam"
#8  
 in "/home/shorty/OpenFOAM/shorty-2.2.x/platforms/linux64Gcc47DPOpt/bin/myBuoyantPimpleFoam"
#9  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#10  
 in "/home/shorty/OpenFOAM/shorty-2.2.x/platforms/linux64Gcc47DPOpt/bin/myBuoyantPimpleFoam"
Gleitkomma-Ausnahme (Speicherabzug geschrieben)
I added a picture of the initial solution.

Regards Tobi
Attached Images
File Type: jpg p.jpg (13.7 KB, 78 views)
File Type: jpg p_rgh.jpg (14.2 KB, 68 views)
File Type: jpg U.jpg (14.8 KB, 65 views)
Tobi is offline   Reply With Quote

Old   November 6, 2013, 11:32
Default
  #19
Senior Member
 
Joachim Herb
Join Date: Sep 2010
Posts: 650
Rep Power: 22
jherb is on a distinguished road
If I read your log file correctly, you don't use the nOuterCorrectors loop. Have you tried nOuterCorrectors > 1 with underrelaxation?
jherb is offline   Reply With Quote

Old   November 6, 2013, 17:34
Default
  #20
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi,

PIMPLE and underrelaxation?
Is underrelaxation not changing the real solution (accuracy in time)?

Well I used nOuterCorrectors > 1 but without success anyway. The error is different. I reach the maximum iteration in the temperature calculation:

Code:
Courant Number mean: 6.92740210013e-09 max: 4.85034908134e-06
deltaT = 1.199999616e-07
Time = 1.2e-07

diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
PIMPLE: iteration 1
DILUPBiCG:  Solving for Ux, Initial residual = 4.38718521517e-07, Final residual = 4.38718521517e-07, No Iterations 0
DILUPBiCG:  Solving for Uy, Initial residual = 4.74501872065e-07, Final residual = 4.74501872065e-07, No Iterations 0
DILUPBiCG:  Solving for Uz, Initial residual = 1.12086811751e-07, Final residual = 1.12086811751e-07, No Iterations 0
DILUPBiCG:  Solving for h, Initial residual = 3.35094034737e-06, Final residual = 2.93432135474e-18, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.997921524511, Final residual = 0.00514407773528, No Iterations 3
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.62324329599e-14, global = 2.43019772121e-17, cumulative = 2.43019772121e-17
PIMPLE: iteration 2
DILUPBiCG:  Solving for Ux, Initial residual = 8.49053274605e-06, Final residual = 1.56889161256e-18, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 9.2706169794e-06, Final residual = 1.7128784731e-18, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 2.42439406856e-06, Final residual = 6.15472389836e-19, No Iterations 1
DILUPBiCG:  Solving for h, Initial residual = 9.4741734031e-05, Final residual = 4.43794077117e-17, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.19770073244, Final residual = 0.00135321069298, No Iterations 3
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.92499613563e-15, global = -2.83812616391e-17, cumulative = -4.07928442704e-18
PIMPLE: iteration 3
DILUPBiCG:  Solving for Ux, Initial residual = 5.83420314596e-06, Final residual = 9.42862909442e-19, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 6.40245339442e-06, Final residual = 1.01498615559e-18, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 1.25166849944e-06, Final residual = 2.97094658592e-19, No Iterations 1
DILUPBiCG:  Solving for h, Initial residual = 0.999998344609, Final residual = 1.3555675042e-14, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.999975236161, Final residual = 9.72118583228e-07, No Iterations 53
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 9.88922463867e-14, global = -5.09467127861e-15, cumulative = -5.09875056304e-15
ExecutionTime = 55.77 s  ClockTime = 56 s

Courant Number mean: 8.77396468445e-05 max: 0.116223720973
deltaT = 5.162455599e-08
Time = 1.71625e-07

diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
PIMPLE: iteration 1
DILUPBiCG:  Solving for Ux, Initial residual = 0.157070886327, Final residual = 5.76405070912e-06, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.150534403994, Final residual = 6.62063104725e-06, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 0.0099884610888, Final residual = 9.50614332261e-07, No Iterations 1
DILUPBiCG:  Solving for h, Initial residual = 0.999999999998, Final residual = 1.22959247587e-07, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.999999956955, Final residual = 0.00978329204882, No Iterations 132
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = -0.00980931633566, global = 1.15347141494e-05, cumulative = 1.15347141443e-05
PIMPLE: iteration 2
DILUPBiCG:  Solving for Ux, Initial residual = 0.999932390446, Final residual = 0.0990621421236, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.999999756929, Final residual = 0.0923265680759, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 0.998134013837, Final residual = 0.046339171224, No Iterations 3
DILUPBiCG:  Solving for h, Initial residual = 1, Final residual = 0.0804871336416, No Iterations 25


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

    From function thermo<Thermo, Type>::T(scalar f, scalar T0, scalar (thermo<Thermo, Type>::*F)(const scalar) const, scalar (thermo<Thermo, Type>::*dFdT)(const scalar) const, scalar (thermo<Thermo, Type>::*limit)(const scalar) const) const
    in file /home/shorty/OpenFOAM/OpenFOAM-2.2.x/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 76.

FOAM aborting

#0  Foam::error::printStack(Foam::Ostream&) in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#1  Foam::error::abort() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libOpenFOAM.so"
#2  Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::T(double, double, double, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double, double) const, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double, double) const, double (Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>::*)(double) const) const in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
#3  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::polynomialTransport<Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>, 8> > >::calculate() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
#4  Foam::heRhoThermo<Foam::rhoThermo, Foam::pureMixture<Foam::polynomialTransport<Foam::species::thermo<Foam::hPolynomialThermo<Foam::icoPolynomial<Foam::specie, 8>, 8>, Foam::sensibleEnthalpy>, 8> > >::correct() in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/lib/libfluidThermophysicalModels.so"
#5  
 in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/bin/buoyantPimpleFoam"
#6  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#7  
 in "/home/shorty/OpenFOAM/OpenFOAM-2.2.x/platforms/linux64Gcc47DPOpt/bin/buoyantPimpleFoam"
Abgebrochen (Speicherabzug geschrieben)
Tobi is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 20:00.