[harly]

Hi,

I am new to blockMesh - and I want to mesh a sphere - I looked at some simple cases like a square cylinder but I am not quite sure how to apply my knowledge.

The mesh for the sphere should be fine enough to perform calculations with turbulence models and getting a fair average Cl and Cd.

Maybe someone could just send me a link to a similar mesh or a description of creating one.

thanks for your time
- harly

[aunola]

I have done turbulent flows around a sphere. I used snappyHexMesh to create the mesh. You need an STL of the sphere for that. I used Gmsh to create that STL.

[harly]

Hi,

thank you for your answer - I have downloaded gmsh and will have a closer look at it tomorrow - but in the meantime I have to admit I have never used snappyHexMesh before - will I be fine with the explanations from the Users Guide ?
Maybe you could send me an samplefile.

And on an other topic what Re-numbers did you use for your turbulent flow around the sphere and do you have any results(or the testcase itself - but I don't want to ask too much) I could use to compare my future results to? - depends on what you did with the flow and which turbulent model you where using - but I would love to compare my modified kEpsilon model to one of your results.

thanks a lot
-harly

[aunola]

The documentation of snappyHexMesh is a bit terse for my taste. You will probably need to experiment a bit with it to get a feel for the meaning of the many adjustable parameters. The guide is enough to get you going though. The basic procedure is very simple. You just need an STL of the sphere and a blockmesh of the space it is embedded in.

The Gmsh user guide is very good. You can even find an example of how to make a sphere in the examples section in the back.

I cannot find my simulations just now (I moved on sine then). If I manage to dig them out I will mail them to you.

I do not have much patience for k-e; all my sims where k-w in the range Re 50-1000. I did simulations to compare Cd values with published experimental results. I got very good results.

[harly]

Hi,

did you have time to dig? I will start playing around with snappyHexMesh today and your files would get useful in the coming weeks, so if you could find the time to search for them I would be very happy.

- harly

[aunola]

Yes, I dug out a blockMeshDict, snappyHexMeshDict and an STL of a sphere (with radius 1 I think). The files are too big to be posted here. If you post your email address I'll send them to you.

I do not remember what Re I used the resulting mesh for. Also, I haven't found the other dictionary files necessary to set up the simulation, but I'll dig some more when I have time.

[harly]

Hi,

thank you very much, yesterday I played around with the motorcycle testcase and I tried to replace the motorcycle with a sphere but the result was horrible.

here my email address:

openfoam.messageboard at gmail.com

again thank you for your effort.

- harly

[Faizan Saifullah]

hi
i am new to openFoam and I also want to do external meshing of sphere but I have to do it using blockmesh ...any help if available?