code_saturne User's Forum

Sorry for the usual lag, I just collected the data of the last 3 tests: test01: - simplec and improved pressure interpolation test02: - simple test03: - simplec, tstep = 0.01 (1/10 wrt. previous tests) and biCGstab when trying to plot streamlines with Salome/ParaVIS, it looks like there's something ...

I've completed a simulation with: - SIMPLEC algorithm - reference time step 0.01 (1/10 than before) - BiCGstab with 1e-5 precision It took almost 19 hours over the weekend. Courant number is now <20 almost everywhere and regions >1 are small. "c Velocity" is about 60-70 at each step. The o...

Most of the time I work with this kind of valves:
The component labeled with 2 is the spool that I place in different positions so that different connections and openings are made.

Antech:
In my case there are small regions where Courant number is > 100.
I'll try to switch to BiGCStab.

Thank you
Claudio

Hallo, sorry for the delay. I had a look at the listing files and saw that Courant number is way off (greater than 1 for SIMPLEC simulations). So the next step will be to play with time step. Are there any good practices to set minimal/maximal time step factor and maximal variation or should I just ...

Thank you Antech for the ideas you shared. I'm planning to make more tests on the basis of your suggestions, when I have enough machine-time. I must also learn how to make good meshes. Yvan, I made a new experiment, changing the Velocity-Pressure algorithm, from SIMPLEC to SIMPLE and it looks like i...

Thank you Yvan. In my experience, working with a subset of the mesh (only the near-valve area) leads to difficult convergence, in particular because outlet conditions are not met. I can definitely work with a slightly coarser mesh and/or the simplest possible geometry, at least for comparison. In th...

Yvan I've just finished the simulation with IPHYDR and there is no difference between those and the previous ones with same conditions (k-eps and Sat 4) at least in terms of pressure at inlet and outlet. I can post more detailed information if you need. btw it took me almost 'forever' (about 40 hou...

I've finished the simulation with k-eps and sat2.
I attach listing and comparison of the results.

Claudio

Thank you Yvan for your answer.
Here I've attached the listing files of the 3 simulations.
Now I'm running the same experiment with Saturne 2 and K-epsilon turbulence model.
I'll post the results as soon as it finishes.
Then I'll try your other suggestions.

Regards
Claudio