[milad092]

Hi every one,

I want to simulate an airfoil that have pitching motion. I used a dynamic mesh with rectangular domain and inner circle for pitching. my boundary condition are velocity inlet and pressure outlet and for circle is interface. I dont know what is the problem with the software that change the interface to wall.

is there any one who could help me to solve it?

thanks

[pbrady2013]

Originally Posted by milad092

Hi every one,

I want to simulate an airfoil that have pitching motion. I used a dynamic mesh with rectangular domain and inner circle for pitching. my boundary condition are velocity inlet and pressure outlet and for circle is interface. I dont know what is the problem with the software that change the interface to wall.

is there any one who could help me to solve it?

thanks

Hi Milad,


Sounds like you are at least starting with a simple geometry to test before adding complexity. Have you compared against the dynamic mesh tutorials?


Have you examined the logs to see if there are any warnings or messages that may guide you?


Cheers,
-pete

[milad092]

Hi Pete,

Thank you for your answer.
In fact i generate my mesh in gambit. I could send my mesh and OF case to you.
At this moment there is no warning but my mesh have some problems i dont why???

[pbrady2013]

Originally Posted by milad092

Thank you for your answer.
In fact i generate my mesh in gambit. I could send my mesh and OF case to you.

If its a small enough mesh to send through then yes, post here, and I (or others) can have a quick look at it. It will most likely be tomorrow Sydney time for me though. If its larger send me PM for my email address and we can do a WeTransfer link.



Have you tried running the same mesh with something very simple: like simpleFoam? This could be good to first try to isloate if there is a mesh problem.

Originally Posted by milad092

At this moment there is no warning but my mesh have some problems i dont why???

Strange, OpenFOAM is usually pretty good at keeping you informed as to what its done.


As you are starting from Gambit and transforming, have you tried to run checkMesh to see if the conversion went OK?


I regularly convert from Gmsh, Salome and CFD-GEOM meshes and find a combination of checkMesh and looking at the mesh in Paraview is great to look at the quality of the conversion.


Cheers,
-pete

[milad092]

Thank you for your response.
I did the simple foam first but for oscillating airfoil i need a dynamic mesh, because of cell problems.
These are the my case in OF.


http://s9.picofile.com/file/83377483...otion.rar.html

[pbrady2013]

Hi Milad,

Thanks for posting. I had a quick look and there are two things to look at:

1) Double check your mesh from Gambit.
First, I like the attempt at a boundary layer mesh but I think you need some better refinement around the trailing edge. See the image: trailingEdge.png. Not really relevant to the case not running though...

Second, checkMesh is flagging multiple mesh regions in the model:

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
   *Number of regions: 2
    The mesh has multiple regions which are not connected by any face.
  <<Writing region information to "0/cellToRegion"
  <<Writing region 0 with 10644 cells to cellSet region0
  <<Writing region 1 with 14006 cells to cellSet region1

I think this is the main problem here. See the attached image boundaries.png. The three edges highlighted are flagged as boundaries. Do you need this complexity?



2) I was running OpenFOAM 1806+ on a CentOS 7 box and the case you sent through to me was incomplete as I could not start it up, see:

Starting time loop

Courant Number mean: 1.8248e-05 max: 0.0243853
deltaT = 5.99988e-06
Time = 5.99988e-06

PIMPLE: iteration 1
GAMG:  Solving for cellDisplacementx, Initial residual = 0, Final residual = 0, No Iterations 0
GAMG:  Solving for cellDisplacementy, Initial residual = 1, Final residual = 8.60638e-18, No Iterations 1


--> FOAM FATAL IO ERROR: 
'pcorrFinal' not found in dictionary "/home/peterb/OpenFOAM/peterb-v1806/run/airfoil_motion/system/fvSolution.solvers"

file: /home/peterb/OpenFOAM/peterb-v1806/run/airfoil_motion/system/fvSolution.solvers

    From function const Foam::dictionary& Foam::dictionary::subDict(const Foam::word&) const
    in file db/dictionary/dictionary.C at line 456.

 FOAM exiting

Have you confirmed that this mesh runs with the standard pimple or simple solver?

Good luck,
-pete

[milad092]

Dear Pete,

Thank you again for your time and respond.
I use this kind of mesh for my pitching airfoil to avoid negative volume.
I simulate pimple and simple foam with completely different mesh.
I attached two mesh for normal simple and pimpleDyM foam to show what are they different.
I do not know why OF recognize circle face as a default walls?!!
Dynamic.msh is for pimpledym foam
mesh0012.msh is for simple foam.
https://files.fm/u/9wweu4j8

Regards,
Milad

[pbrady2013]

Hi,


I'm out of the office today with clients but will have a look at this when I get back.


My logic for trying the same meshes is that I find what works for me is to start basic and build complexity. In this case I'd do what you have with simpleFoam and pimpleFoam but instead of having a completely different mesh for the moving I'd try to keep this as similar as possible and try to use the same base mesh construct across all simulations.



Can you quickly drop this mesh designed for dynamic into your simple/pimple models to test?


-pete

[milad092]

Hi,

I want to simulate pitching airfoil with normal mesh (simple foam). But there is a error about the size in the P and U folders. I do run simple foam with good results but i did it with dynamic mesh and there is no results. I think because of the boundary condition around circle the OF can not catch the fluid behavior around airfoil.
This is the case(wing motion pimpledymfoam) that i run with simple mesh.

https://files.fm/u/u479eq7n

Thank you for your time
Milad