Problem Meshing Airfoil
 

Hi ,

It's my first post as openFOAM 1.5 user, I meshed an airfoil but it's supposed that it should have a zone without mesh in the airfoil region, although I see the airfoil boundary, the mesh doesn't take care. It would be OK if someone take a look of the mesh and airfoil boundary pictures attached.

Thank you.

Hi erodv,

may I ask you some things?
In particular:
1) do you define a block inside the airfoil?
2) is your mesh 3D? (or is it only a display effect?)

Regards,

Daniele

(SOLVED) Sorry, it was an error defining the blocks
 

Hi,
Sorry, :p I defined blocks intersecting the inner airfoil section, that was the problem, now all is ok with the mesh. :) Thanks to Dani for take the time to post.

Not at all, erodv!

May I ask you a thing?
Do you have an experience with mesh generators different from blockMesh? If yes ... what's the best for external flows in your opinion?

Many thanks

Daniele

I don't have experience with open source mesh generators, but I found something about a programm called gmsh, the mesh generated can be imported into openfoam, (i don't try it yet). And from the commercial ones, there are many options, for example Fluent - Gambit meshes can be imported into openFOAM.

hi dani, hi erodv,

I also meshed many airfoil in my diploma thesis and collected much experience.

1. salome is feasible to mesh airfoils, but the mesh quality is not that good.
2. Blockmesh can mesh an airfoil very quick with only 6 blocks
3. if you want to mesh many airfoils with a very excellent mesh, you can creat many many blocks. so eg. i have and airfoil spline/polyline with 180 vertices, then I create a mesh consisting of 180 blocks. between each vertex one block. therefore you need to take those vertices and translate them rectangle to the surface to create the matching vertices.
since the topology of blockMesh is very simple and always works after the same procedure, one can automatizes this work in excel with VBA eg.

to make it clearer, I attached some pictures. the resulting mesh then is very good.

remember: since you probably are solving with simpleFOAm or turbFoam, the y+ value should be around 30. don't make the mistake and shrink it to 1. 1 only works with icofoam or LES.

Hi everyone!

I also simulate some airfoils with OpenFOAM. However things I try to simulate are part of a gas turbine, so I need a compressible solver with turbulence modelling possibility. I use the rhoSimpleFoam. All my meshes are imported from Turbogrid. I try to compare my results to CFX but they are still different mainly in the dissipation. Have you maybe already done some comparasions of OpenFOAM to commercial codes? Do you have maybe some experience you would like to deal with? I would be pleased for any anwser.

Regards, Marcin.

Hi Marcin,

No, I don't have experience simulating the gas turbine, I'm relative new in both commercial and open source codes.

Hi wolle1982,


What code did you use in blockMesh to create your spines?

I attempted using the function simpleSpline, in the format "simpleSpline A B ((i j k) (l m n))" with no luck.

Thanks for your help!

hi,

nether...nor. Using my math-knowledge, I programmed a function in excel that creates a spline consisting of many points with a definable gradient at the end and at the beginning. with those points I created a usual "polyLine". this makes good results. I hope some day a new OF version corrects that bug.

good luck.

airfoils with openfoam
 

Hai everybody. I am new to OpenFOAM .I need to work with some airfoil geometry in OpenFOAM. I used to mesh an airfoil in gambit and solving it using fluent (2D). I need to do it with OpenFOAM , I tried import gambit mesh to OpenFOAM but it failed with some error messages. can anybody give me an idea about converting the fluent mesh file to OpenFoam and solving it with the same.
Thank you

hi prasanth
am also doing a cascade airfoil problem,why dont you post your error message

can anyone tell me how C grid is made in salome ??