[shock77]

I think it was at 8e-5 seconds, if I remember correctly. At least somewhere in this range, I have already deleted the case.


Yeah the momenTransport folder must be new, I dont know this one. Also I dont work with the newer versions so I cannot help you with that. Also the error is not helpfull.


I didnt use the setFields folder, I just waited until it converges. It was stable enaugh although the velocity wasnt zero.


At least it is possible, you just have to transfer it to your version somehow.

[Malkocoglu]

Originally Posted by shock77

I think it was at 8e-5 seconds, if I remember correctly. At least somewhere in this range, I have already deleted the case.


Yeah the momenTransport folder must be new, I dont know this one. Also I dont work with the newer versions so I cannot help you with that. Also the error is not helpfull.

I didnt use the setFields folder, I just waited until it converges. It was stable enaugh although the velocity wasnt zero.


At least it is possible, you just have to transfer it to your version somehow.

constant/momentumTransport and constant/thermophysicalProperties files have been in OF versions for a while. But I do not know the exact reason for being different files from constant/transportProperties and constant/turbulenceProperties. By the way, I tried your files and settings with OF v8 instead of my currrent version OF-dev) and it seems to work uninterruptedly (at least for the first 1e-5 secs). But OF v8 needed constant/momentumTransport and constant/thermophysicalProperties as well, it did not begin running until I put these files in /constant directory.

I will keep this run going until it explodes (hopefully never happens) and see what happens. The case is arranged as inviscid; I do not know what will become if I run with turbulence model.

I expect to give some outputs if I can maintain the actual run.

Thank you again @shock77, your contribution is invaluable. And as I always said, please do not disappear on the forum; probably I will need to confer with you again.

Best,
Malkocoglu

[shock77]

Glad it works so far and that I could help.


I hope it doesnt blow up!


Keep up the good work and have a nice start in the new year.




And I will stay here in this forum for a while I guess haha.

[Malkocoglu]

Originally Posted by shock77

Glad it works so far and that I could help.


I hope it doesnt blow up!

Keep up the good work and have a nice start in the new year.

And I will stay here in this forum for a while I guess haha.

Thank you @shock77 for the good wishes. I hope the same for you.

I run the case with OF8 which is different from my older one. It did not blow for 15e-5 seconds and I interrupted.

On the other hand, when I checked the boundary conditions that given by you, they correspond to Mach 1.5 whereas my case has 2.95. Similarly, pressure ratio and temperature values in your modified files are around 10 and 200 K, respectively. In my situation, these values should be around 150-160 and 100-110 K, again respectively. Then, I guess that my temperature is so low that it reaches 0 or its near values.

Best,
Malkocoglu

[Malkocoglu]

Originally Posted by Malkocoglu

Thank you @shock77 for the good wishes. I hope the same for you.

I run the case with OF8 which is different from my older one. It did not blow for 15e-5 seconds and I interrupted.

On the other hand, when I checked the boundary conditions that given by you, they correspond to Mach 1.5 whereas my case has 2.95. Similarly, pressure ratio and temperature values in your modified files are around 10 and 200 K, respectively. In my situation, these values should be around 150-160 and 100-110 K, again respectively. Then, I guess that my temperature is so low that it reaches 0 or its near values.

Best,
Malkocoglu

So, if the case files still stay in your computer, could you adjust the case in a way that Mach 2.95 and jet total pressure ratio 150? Because when I do that, the case insists to blow. And you solved with rhoCentralFoam, right?

[shock77]

Hi again,


unfortunately I have deleted the case.


Do you still have troubles with that? That might be due to negative temperatures. Also when it comes to low temperatures, the sutherland law might be not applicable. You should check that for your gas!

[Sakun]

Hi ,


did you mange to solve your issue, if so can provide the solution? cause i am having the same phenomena for my steady-state compressor blade simulation.

[forAurora]

Originally Posted by Tobi

Right now, I am dealing with reactingFoam and a methane injection into a exhaust pipe system. Here, I get acoustic pressure waves moving from inlet to outlet (here it is reflected) and then back to the inlet. The reflecting of the pressure at the outlet boundary is not real however and maybe I should re-set somehow the BC.

Hi Tobi, would you please explain in detail how to eliminate this reflected wave?

I'm currently simulating jet flame with reactingFoam. Starting from SandiaD_LTS in the tutorial, which I would like to transform into a 3D LES case (WALE). During simulation, after switching the combustion on, a wave appears immediately in the pressure/velocity field. This wave seems to be reflected at the exit, and soon after the reflected waves are superimposed causing the calculation to diverge? (as shown in the video below)

I've tried several combinations of p and U for outlet BC, including p(totalPressure)+U(pressureInletOutletVelocity), p(waveTransmissive/zeroGradient)+U(waveTransmissive/ zeroGradient). But there is always reflected waves in the result, only the divergence time is different.

The temperature field in the result of each case seems to be ok. In addition, I found the species fields in the result is very strange, as in the video below, t=0.2 turn on the combustion, after that the mass fraction of CH4 will undergo abrupt changes in chunks. Is it the key to divergence, rather than waves?

Anyway, can you advise on how to simulate a jet flame using reactingFoam, how to adjust the boundary conditions to eliminate reflected waves, or where should I start to solve the anomalous changes in the species field? Thanks a lot!!!