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March 4, 2008, 07:18 
Hi Marco,
send me a mail w

#21 
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Francesco Boschetto
Join Date: Mar 2009
Location: Italy
Posts: 56
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Hi Marco,
send me a mail with your case and I'll have a look at it, probably there is something wrong My first suggestion is to avoid using FoamX, modify the files is often better and makes you understand more the code. Second suggestion is to look at tutorials which are similar to your case, you'll find useful informations. Regards Francesco 

March 4, 2008, 08:14 
Hi Thomas and Francesco,
I

#22 
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Marco Zardetto
Join Date: Mar 2009
Location: Italy
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Hi Thomas and Francesco,
I added my email in my profile, you'll see it clicking on my name. If you send me a mail I'll reply to you. I don't see your email adress. I thank you for your kindness Regards 

March 4, 2008, 08:57 
Hi Marco ,
About your previ

#23 
Senior Member
Cedric DUPRAT
Join Date: Mar 2009
Location: Belgium
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Hi Marco ,
About your previous error, just keep in mind that when you've sigFpe somewhere, it's often because you divide by zero somewhere. are you sure about your BC ? what are your initial values (k, epsilon) not only at your Patches but also your internal field value? and, as said Francesco, tutorials are usually a good starting point. Regards, Cedric 

March 4, 2008, 15:19 
Hi Cedric,
no I was not sur

#24 
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Marco Zardetto
Join Date: Mar 2009
Location: Italy
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Hi Cedric,
no I was not sure and now I can say they were wrong. I can't use a steady state solver with those BC, is it true? Anyway I changed BC and maybe the simulation is right now. Regard Marco 

March 11, 2008, 19:27 
hi, what relaxation factors ar

#25 
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Laurence Griffiths
Join Date: Mar 2009
Location: Bristol, UK
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hi, what relaxation factors are you using for rhoSimple Foam?
I had similar errors not too long ago due to wrong choice of factors patankar [numerical heat transfer and fluid flow] suggests as a guidance: 0.2(pressure) 0.8(velocity) and that pressure+velocity factor = 1(approx) also at the start of the iterations it may be useful to underrelax it by quite a lot (especially pressure)  not too sure on velocity  either trial & error, or maybe somebody who knows a little more than me can give some better input sorry not too sure what your k&epsilon values should be, perhaps there's some published literature on it? also francesco's advice to run the cases by hand is worth taking  i had a couple of problems with foamX not filling in the boundary conditions correctly. 

April 23, 2008, 11:07 
Hi everybody,
I'm trying to

#26 
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Leonardo Nettis
Join Date: Mar 2009
Posts: 72
Rep Power: 9 
Hi everybody,
I'm trying to use rhoSimpleFoam to analyze a rae2822 profile (Ma=0.75). Starting from a case located in the rhoExplicitPorousSimpleFoam tutorial I made some minor corrections due the slightly different solver. Unfortunately this is what I get after 34 timesteps:  Starting time loop Time = 0.001 DILUPBiCG: Solving for Ux, Initial residual = 0.91642, Final residual = 0.00113156, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.497643, Final residual = 0.000109773, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 0.000153941, Final residual = 0.000153941, No Iterations 0 DICPCG: Solving for p, Initial residual = 1, Final residual = 0.085924, No Iterations 10 time step continuity errors : sum local = 0.00341069, global = 6.72999e18, cumulative = 6.72999e18 bounding p, min: 183403 max: 51509.8 average: 14986 rho max/min : 0.434091 0.394052 DILUPBiCG: Solving for epsilon, Initial residual = 1, Final residual = 0.0760585, No Iterations 1 DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 4.01958e10, No Iterations 1 ExecutionTime = 1.1 s ClockTime = 2 s Time = 0.002 DILUPBiCG: Solving for Ux, Initial residual = 0.625658, Final residual = 0.0132899, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.597063, Final residual = 0.0160514, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 1, Final residual = 0.0581808, No Iterations 1 DICPCG: Solving for p, Initial residual = 0.999938, Final residual = 0.0994651, No Iterations 128 time step continuity errors : sum local = 0.371864, global = 5.50248e16, cumulative = 5.43518e16 bounding p, min: 3.58449e+07 max: 1.04555e+11 average: 2.88087e+10 rho max/min : 81429.1 0.407813 DILUPBiCG: Solving for epsilon, Initial residual = 0.538868, Final residual = 1.87952e14, No Iterations 1 DILUPBiCG: Solving for k, Initial residual = 0.494746, Final residual = 2.88931e11, No Iterations 1 ExecutionTime = 1.56 s ClockTime = 2 s Time = 0.003 DILUPBiCG: Solving for Ux, Initial residual = 0.131877, Final residual = 0.0081574, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.588281, Final residual = 0.0125537, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 0.984923, Final residual = 0.0415359, No Iterations 1 DICPCG: Solving for p, Initial residual = 0.999974, Final residual = 0.0957307, No Iterations 1 time step continuity errors : sum local = 3.01611e+06, global = 2.06632e09, cumulative = 2.06632e09 bounding p, min: 2.18384e+14 max: 3.72087e+16 average: 5.03564e+12 rho max/min : 2.89787e+10 1.59075e+10 DILUPBiCG: Solving for epsilon, Initial residual = 0.994871, Final residual = 1.6861e08, No Iterations 1 bounding epsilon, min: 26760.4 max: 4.40476e+23 average: 2.87204e+19 DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 1.60288e08, No Iterations 1 bounding k, min: 21.8637 max: 5.49352e+17 average: 3.58298e+13 ExecutionTime = 1.81 s ClockTime = 2 s Time = 0.004 DILUPBiCG: Solving for Ux, Initial residual = 0.654315, Final residual = 0.0018068, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.192592, Final residual = 0.000735478, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 0.169146, Final residual = 0.000217519, No Iterations 1 > FOAM FATAL ERROR : Maximum number of iterations exceeded#0 Foam::error::printStack(Foam:stream&) in "/home/nettis/OpenFOAM/OpenFOAM1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so" #1 Foam::error::abort() in "/home/nettis/OpenFOAM/OpenFOAM1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so" #2 Foam::hThermo<foam::puremixture<foam::consttranspo rt<foam::speciethermo<foam::hc onstthermo<foam::perfectgas> > > > >::calculate() in "/home/nettis/OpenFOAM/OpenFOAM1.4.1/lib/linux64GccDPOpt/libbasicThermophysical Models.so" #3 Foam::hThermo<foam::puremixture<foam::consttranspo rt<foam::speciethermo<foam::hc onstthermo<foam::perfectgas> > > > >::correct() in "/home/nettis/OpenFOAM/OpenFOAM1.4.1/lib/linux64GccDPOpt/libbasicThermophysical Models.so" #4 main in "/home/nettis/OpenFOAM/OpenFOAM1.4.1/applications/bin/linux64GccDPOpt/rhoSimple Foam" #5 __libc_start_main in "/lib64/libc.so.6" #6 Foam::regIOobject::readIfModified() in "/home/nettis/OpenFOAM/OpenFOAM1.4.1/applications/bin/linux64GccDPOpt/rhoSimple Foam" From function specieThermo<thermo>::T(scalar f, scalar T0, scalar (specieThermo<thermo>::*F)(const scalar) const, scalar (specieThermo<thermo>::*dFdT)(const scalar) const) const in file /home/dm2/henry/OpenFOAM/OpenFOAM1.4.1/src/thermophysicalModels/specie/lnInclud e/specieThermoI.H at line 83. FOAM aborting  I hope somebody can help me!!! thank you in advance, dino 

April 23, 2008, 12:02 
ps: I forgot to specify that I

#27 
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Leonardo Nettis
Join Date: Mar 2009
Posts: 72
Rep Power: 9 
ps: I forgot to specify that I've imported the 0/U file from the solution found with potentialFoam. This one seems to be corrected, but I don't know if it could influence the problem I've shown in my previous post!!
dino 

May 8, 2008, 16:58 
Hi Leonardo, I'm trying to do

#28 
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Daniele Bonetti
Join Date: Mar 2009
Posts: 3
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Hi Leonardo, I'm trying to do a similar experiment to yours (RAE2822 at M=0.72) but I've a lot of troubles trying to set up the simulation with rhoSimpleFoam. I'm trying to use a test case from rhoExplicitPorousSimpleFoam but it does not work. Could you send me your test file (without the mesh, I use a mesh converted from Gambit) so maybe I can progress? I hope you can help me.
Thanks a lot Daniele 

October 23, 2008, 08:18 
Hi Fomers,
I am working wit

#29 
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Vishal Jambhekar
Join Date: Mar 2009
Location: University Stuttgart, Stuttgart Germany
Posts: 90
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Rep Power: 9 
Hi Fomers,
I am working with the prism case in sonicTurbfoam, but i want to capture the shoch at the prism surface.for Mach number 3. i have created mesh for that accordingly. but.....i am unable to find the grad rho at the surface of the prism. Can i use other foam for this case for compressible flow and steady state so that i can capture grad roh at surface.
__________________
Cheers, Vishal Jambhekar... "Simulate the way ahead......!!!" 

October 23, 2008, 08:21 
Hi,
ihacve one more query

#30 
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Vishal Jambhekar
Join Date: Mar 2009
Location: University Stuttgart, Stuttgart Germany
Posts: 90
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Hi,
ihacve one more query i dont have foamX directory in the OpenFoam 1.5 version i have installed. till now i was working with command prompt. Can anyone tell me how can i get in as i want need it to deal with complex scinario. Thanks
__________________
Cheers, Vishal Jambhekar... "Simulate the way ahead......!!!" 

November 18, 2008, 06:48 
Hello,
could anyone please

#31 
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Posts: n/a

Hello,
could anyone please translate the hEqn implemented in rhoSimpleFoam into mathematical language, please? Most of all, I am interested in figuring out whether the total or the static enthalpy is used. The equation for total enthalpy (steady state) found in literature looks like this: Ñ(r U h<sub>tot</sub>) = Ñ(l Ñ T) + Ñ(U t) + S<sub>E</sub> h<sub>tot</sub> = h + 0.5 U<sup>2</sup> Ñ(U t) = viscous dissipation S<sub>E</sub> = source term C++ code: fvScalarMatrix hEqn ( fvm::div(phi, h)  fvm::Sp(fvc::div(phi), h)  fvm::laplacian(turbulence>alphaEff(), h) == fvc::div(phi/fvc::interpolate(rho)*fvc::interpolate(p, "div(U,p)"))  p*fvc::div(phi/fvc::interpolate(rho)) ); Thank you very much, Paul 

November 19, 2008, 08:31 
OK, answering my question myse

#32 
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Posts: n/a

OK, answering my question myself:
The enthalpy equation is impemented in terms of static enthalpy, making the C++ code appear in mathematical language: fvm::div(phi, h) = ÑÂ•(rU h) fvm::Sp(fvc::div(phi), h) = S<sub>E</sub> (source term, not sure about this) fvm::laplacian(turbulence>alphaEff(), h) = ÑÂ•(a<sub>eff</sub>Ñh) fvc::div(phi/fvc::interpolate(rho)*fvc::interpolate(p, "div(U,p)")) = ÑÂ•(p U) p*fvc::div(phi/fvc::interpolate(rho)) = p ÑÂ•U Consequently: ÑÂ•(rU h)  S<sub>E</sub>  ÑÂ•(a<sub>eff</sub>Ñh) = ÑÂ•(p U)  p ÑÂ•U where ÑÂ•(p U)  p ÑÂ•U = U Â•Ñp That means the viscous dissipation term t:ÑU is not implemented. I have added a viscous term into the equation, but instead of rising the temperature decreases! Where is my mistake? My enthalpy equation: volSymmTensorField tau(turbulence>devRhoReff()); volScalarField tauGradU = tau && fvc::grad(U); fvScalarMatrix hEqn ( fvm::div(phi, h)  fvm::Sp(fvc::div(phi), h)  fvm::laplacian(turbulence>alphaEff(), h) == fvc::div(phi/fvc::interpolate(rho)*fvc::interpolate(p, "div(U,p)"))  p*fvc::div(phi/fvc::interpolate(rho)) + tauGradU ); 

November 21, 2012, 05:27 
Check Sign of Dissipation

#33 
New Member
Join Date: Mar 2010
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Hi paul_mathis,
did you solve this problem within the last 4 years? It seem likely that the dissipation (turbulence>devRhoReff() && fvc::grad(U)) has the wrong sign for an unknown reason. I created a dissipation field, displayed it in paraFoam and got negative values in the whole field. I think implementing Phi with (turbulence>devRhoReff() && fvc::grad(U)) should solve the problem. Is anyone familiar with the sign conventions of either the viscous stresses or the velocity gradient in openFoam? regards Bastian 

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