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June 4, 2013, 04:20 |
sonicFoam for turbulent flow at M=3
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#1 |
Member
Felipe Alves Portela
Join Date: Dec 2012
Location: FR
Posts: 70
Rep Power: 13 |
Hello all,
I have been trying to get a solution for a supersonic turbulent channel flow. I managed to get sonicFoam working for a Mach number (based on wall temperature) of about 1.5 - t1.png. To achieve this I simply add a momentum source term to the UEqn and eEqn. When I try to get to M ~ 3 - t2.png - the simulation crashes during laminar-turbulent transition with the following message: Code:
[15] --> FOAM FATAL ERROR: [15] Maximum number of iterations exceeded [15] [15] From function specieThermo<Thermo>::T(scalar f, scalar T0, scalar (specieThermo<Thermo>::*F)(const scalar) const, scalar (specieThermo<Thermo>::*dFdT)(const scalar) const) const Cheers, Felipe |
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June 4, 2013, 06:58 |
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#2 |
Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 26 |
hi
I didn't get what you mean exactly. I thought sonicFoam is suitable for all Mach numbers!really its not good for supersonic flows? If its so why you don't use rhoCentralFoam?i think its certaily appropriate for all regimes of flows.
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Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. |
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June 4, 2013, 07:14 |
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#3 | |
Member
Felipe Alves Portela
Join Date: Dec 2012
Location: FR
Posts: 70
Rep Power: 13 |
Quote:
I didn't say sonicFoam doesn't work for supersonic flows, just that I can't manage to get my test case working. I am aware my original post was a bit vague, but the problem is I don't know where the bug is hiding, though I would expect this to be an issue with the way I set up the case, rather than the solver itself! I'll give it a go with rhoCentralFoam and see if it helps. Though I'm still curious about why this doesn't work... UPDATE: Hi again, So I took the last time step from the crashed case and let it run with rhoCentralFoam (no momentum source now) and it still crashes (same error message) after some iterations. |
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June 4, 2013, 08:30 |
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#4 |
Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 26 |
Hi
what are your BC's? could you attach them here? and why you want to add a source term?and it should be frmo Mach type? could you attach your modified solver?
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Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. Last edited by immortality; June 4, 2013 at 09:51. |
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June 4, 2013, 08:44 |
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#5 |
Member
Join Date: Sep 2012
Posts: 60
Rep Power: 13 |
Hi felipe,
To know exactly what is going wrong, try to debug using gdb. As it is, sonicFoam appears suitable for supersonic flows. I have been successful simulating mach 3 flow (laminar). regards, |
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June 4, 2013, 10:56 |
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#6 | ||
Member
Felipe Alves Portela
Join Date: Dec 2012
Location: FR
Posts: 70
Rep Power: 13 |
Quote:
Hi, I have periodic BC's in the stream- and spanwise directions. Upper and lower walls have no-slip (U = 0), constant temperature (T = 300) and zero gradient on pressure. I have the source term to sustain the flow, otherwise it would just "fade" to rest... Quote:
Yes, I wouldn't expect it to be a problem with the solver. I'll let you know if I find what's wrong! |
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June 7, 2013, 03:46 |
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#7 |
Member
Felipe Alves Portela
Join Date: Dec 2012
Location: FR
Posts: 70
Rep Power: 13 |
Hi again,
I changed the scheme I was using for div(phid,p) from Gauss linear to vanLeer. The simulation now seems to be more stable, however my temperature is reaching extremely low values. I noticed in the tutorials that Gauss limitedLinear 1 is used to discretise this term, shouldn't this affect only the solution for pressure? I sent you a message with the necessary changes |
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June 10, 2013, 10:48 |
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#8 |
Member
Felipe Alves Portela
Join Date: Dec 2012
Location: FR
Posts: 70
Rep Power: 13 |
Hi,
So, I tried the Ma ~ 2 test case with rhoCentralFoam. The result is quite different from that of sonicFoam: I get a bunch of shocks that just reflect from one wall to the other - see attached snapshot. Any ideas? What are the main differences from sonicFoam to rhoCentralFoam that could give such different solutions?! From what I've read on this types of flows, I would not expect such shocks to develop... Last edited by fportela; June 10, 2013 at 18:10. |
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July 12, 2013, 10:19 |
something missing in the energy equation
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#9 |
Member
Felipe Alves Portela
Join Date: Dec 2012
Location: FR
Posts: 70
Rep Power: 13 |
Hi,
In case someone gets a similar issue, just wanted to give the heads up that the viscous term is missing in the energy equation of sonicFoam, in my case this was causing the crash with the temperature decreasing - isothermal wall was extracting energy from the flow, but now heat was produced due to friction Also, I believe the term Code:
p*fvc::div(phi/fvc::interpolate(rho)) Code:
fvc::div(phi/fvc::interpolate(rho), p) |
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