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- Julien de Charentenay
- Hi.
- Julien • 47 mins
- Hi
- 47 mins
- Richard Brook
- Julien de Charentenay
- Let's walk through what to do with the scenario_0.zip.
- I am just copying it somewhere.
- And extract it.
- Are you windows or linux?
- Julien • 46 mins
- windows
- Im considering a linux partition so I can run swak4foam
- 45 mins
- Richard Brook
- Julien de Charentenay
- Do you use blueCFD, blueCFD-SingleCore or another?
- Julien • 45 mins
- if I can figure out how to compile it that is!
- yes I use single core
- 45 mins
- Richard Brook
- Julien de Charentenay
- Re Linux: you can try with an emulator first, but partition will be best. Compilation of swak4foam is reasonably straightforward - in my opinion.
- Do you have the scenario_0.zip extracted?
- Julien • 44 mins
- yes and I have put the file you sent me in there too
- 44 mins
- Richard Brook
- Julien de Charentenay
- Cool.
- Open a blueCFD single core command prompt.
- Julien • 43 mins
- via the start menu options?
- I have:
- Command Line with mingw-w32 DP
- Command Line with mingw-w32 SP
- Command Line with mingw-w64 DP
- 42 mins
- Richard Brook
- Julien de Charentenay
- The last one. It uses 64bit and double precision.
- Julien • 42 mins
- ok done
- 42 mins
- Richard Brook
- Julien de Charentenay
- In the command prompt, change the directory to where the case is located. In my case, I typed: cd C:\Documents and Settings\Dell 330\My Documents\test\scenario_0
- Julien • 41 mins
- hmm, it wont change directory
- 39 mins
- Richard Brook
- Julien de Charentenay
- What is your directory?
- or what is the path to your case?
- Julien • 38 mins
- D:\scenario_0
- 38 mins
- Richard Brook
- Julien de Charentenay
- Try
- d:
- cd scenario_0
- Julien • 38 mins
- ah just d: switched it
- 38 mins
- Richard Brook
- Julien de Charentenay
- The good old DOS world!!!
- I sent you a file via email. Have you received it?
- Julien • 37 mins
- i have
- 37 mins
- Richard Brook
- Julien de Charentenay
- In D:\scenario_0\system there is an existing file snappyHexMeshDict.
- Can you make a copy of the existing one and copy the one I sent over in the directory?
- Julien • 36 mins
- done
- 36 mins
- Richard Brook
- Julien de Charentenay
- The difference between the two file is that the mesh generated by the "new" one will be coarser and will take less time to mesh & run. Once we go through it, you can try again with the "saved" one. ok?
- Julien • 35 mins
- ok, understood. I just added -original to the end of the name of the old one so no probs
- 34 mins
- Richard Brook
- Julien de Charentenay
- Back to the command prompt, type:
- blockMesh
- Julien • 33 mins
- done
- 33 mins
- Richard Brook
- Julien de Charentenay
- surfaceFeatureExtract -includedAngle 150 constant/triSurface/setup.stl setup
- Let me know if there is any error message...
- Julien • 32 mins
- 31 mins
- Richard Brook
- Julien de Charentenay
- ok. Complaining about missing swak4Foam...
- But it looks like it is going through.
- Do you have a file D:\scenario_0\constant\triSurface\setup.eMesh ?
- If yes, it is "working" so far.
- Julien • 28 mins
- yes
- 28 mins
- Richard Brook
- Julien de Charentenay
- Moving on:
- copy system\decomposeParDict.snappyHexMesh system\decomposeParDict
- snappyHexMesh -overwrite
- Julien • 27 mins
- its working away
- 27 mins
- Richard Brook
- Julien de Charentenay
- Me too. I have an old computer, so you will probably get there before me.
- Julien • 26 mins
- mines about 6 years old
- 26 mins
- Richard Brook
- Julien de Charentenay
- Once it is complete, you should be able to load the mesh in ParaView (no solution yet, but you can check the mesh)...
- I stand a chance then...
- Julien • 25 mins
- just finished.
- 24 mins
- Richard Brook
- Julien de Charentenay
- Still waiting....
- Julien • 24 mins
- mine is a quad core Q6600 with 6gb ram.
- 24 mins
- Richard Brook
- Julien de Charentenay
- I give up. I have a Pentium 4 with 1GB ram...
- Julien • 23 mins
- ouch
- 23 mins
- Richard Brook
- Julien de Charentenay
- Mine is still going, but it may catch up later...
- renumberMesh
- Julien • 22 mins
- done
- 22 mins
- Richard Brook
- Julien de Charentenay
- checkMesh
- Julien • 22 mins
- done
- 22 mins
- Richard Brook
- Julien de Charentenay
- simpleFoam
- Julien • 21 mins
- ok, so I assume this is it running the test?
- 20 mins
- Richard Brook
- Julien de Charentenay
- From then, monitor the simulation to check that it converges and when it converges.
- Julien • 19 mins
- how will I know it has converged?
- 19 mins
- Richard Brook
- Julien de Charentenay
- And revert to the full mesh using the original snappyHexMeshDict.
- My snappyHexMesh has finished...
- Julien • 18 mins
- I assume consistent figures under forces and moment?
- 18 mins
- Richard Brook
- Julien de Charentenay
- In short there are two main ways:
- 1) Look at the residuals - in Khamsin I was able to show them as a graph. In this approach, they are shown as the screen outputs:
- Time = 5
- DILUPBiCG: Solving for Ux, Initial residual = 0.151697, Final residual = 3.27574e-008, No Iterations 5
- DILUPBiCG: Solving for Uy, Initial residual = 0.0653019, Final residual = 8.91276e-008, No Iterations 4
- DILUPBiCG: Solving for Uz, Initial residual = 0.0984954, Final residual = 6.35355e-007, No Iterations 4
- GAMG: Solving for p, Initial residual = 0.634272, Final residual = 4.83282e-008, No Iterations 16
- In the above the residuals that matter are the "Initial residual". Until they drop below 1e-3, the simulation is not getting near convergence...
- 2) Once the initial residuals are going below 1e-3, look at flattening out of forces and moments. They should be output on the screen as well as in a file (look at D:\scenario_0\forces_....\0\forces.dat )
- Can you confirm that you can get the above?
- Julien • 13 mins
- i have the .dat file
- 12 mins
- Richard Brook
- Julien de Charentenay
- It is just a text file that you load (probably in excel as well). Have a play around and let me know if you need help.
- Julien • 11 mins
- ok
- 10 mins
- Richard Brook
- Julien de Charentenay
- On another note: your simulation will not include the following: wheel rotations (you would need swak4Foam), and mesh refinement of the front and rear wings.
- Julien • 10 mins
- thats fine
- will the simulation stop at a certain point? currently at Time = 103
- 9 mins
- Richard Brook
- Julien de Charentenay
- To achieve the later (mesh refinement), in the SketchUp model, create groups for the front and rear wings (separate groups are fine) and give the group a name that including "wing" such as "frontwing", "rear-wing".
- Simulation stopping. It is set to run for 1500 iteration (time = 1500), but feel free to stop it whenever you believe that it is complete using either Ctrl+C in the command prompt or kill it through the task manager. The "cleaner" way is to edit the file D:\scenario_0\system\controlDict and change the entry under "endTime" to a value less than the current Time.
- Julien • 7 mins
- thanks for all your help
- 6 mins
- Richard Brook
- Julien de Charentenay
- No drama.
- You may find that the meshing and running will take a lot longer with the "original" snappyHexMesh.
- Julien • 5 mins
- I will probably just stick to the usual way of running simulations through Khamsin as I have no problems with setting that up and getting a result. I will let Dan know about how this went though as he has trouble with the whole CFD installation and running for some reason even though I have shared all the info you have given me in the past
- 4 mins
- Richard Brook
- Julien de Charentenay
- One of the limitation of blueCFD-SingleCore is its inability of running on multiple computers. Linux would be a good alternative to all you to make the most of your resource.
- Let him know that I am available to have a chat online and go through a screencast exercise to set him up.
- Julien • 3 mins
- im definitely going to look into it. I have a number of computers and laptops to hand that I could create a cluster
- will do, thanks again Julien, I'll go have a play and see how things go
- 2 mins
- Richard Brook
- Julien de Charentenay
- If you are moving in that direction, you will probably exceed the current possibilities of Khamsin...
- Julien • 2 mins
- its just an idea 😀
- actually getting there will probably be a different story!
- 1 min
- Richard Brook
- Julien de Charentenay
- Always looking for bigger cases...
- I have some progress margin with my Pentium 4...
- Good luck with it and if you manage to create stunning visual, please share...
- Julien • Now
- Julien de Charentenay
- i will!
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