[Other] OpenFOAM mesh generation of an aerofoil

yrganiri · June 19, 2015, 12:21

Thank you for the help.

I have tried exactly that but I cannot make gmshToFoam to work with what I have and I really don't know what I'm doing wrong.

So, I am using the data points of RAE2822 and surround it with a C-type grid.

It looks like this: Selection_139.png

Now, my problem is that in order to make it look like that, I used many line loops and plane surfaces and I don't know how to name the physical surfaces:

Code:

Physical Surface("back") = {1042,1020,1064,1108,1125,1086}; 
Physical Surface("front") = {50,52,54,55,53,51}; 
......

I am attaching the .geo file naca5012_step3_structured.txt

The gmshToFoam output is:

Code:

...
Mapping region 2 to Foam patch 0
Mapping region 1 to Foam patch 1
Mapping region 4 to Foam patch 2
Mapping region 5 to Foam patch 3
Mapping region 3 to Foam patch 4
Cells:
    total:0
    hex  :0
    prism:0
    pyr  :0
    tet  :0

--> FOAM FATAL IO ERROR: 
No cells read from file "naca5012_step3_structured.msh"
Does your file specify any 3D elements (hex=5, prism=6, pyramid=7, tet=4)?
Perhaps you have not exported the 3D elements?
...

hk318i · June 19, 2015, 12:35

I had a quick look

Code:

Physical Volume("internal") = {50,52,54,55,53,51};

This definition is wrong because you don't have these volumes.

It should be

Code:

Physical Volume("internal") = {1,2,3,4,5,6};

Try it again and see if you have another problem.

Quote:

Originally Posted by yrganiri

Thank you for the help.

I have tried exactly that but I cannot make gmshToFoam to work with what I have and I really don't know what I'm doing wrong.

So, I am using the data points of RAE2822 and surround it with a C-type grid.

It looks like this: Attachment 40246

Now, my problem is that in order to make it look like that, I used many line loops and plane surfaces and I don't know how to name the physical surfaces:

Code:

Physical Surface("back") = {1042,1020,1064,1108,1125,1086}; 
Physical Surface("front") = {50,52,54,55,53,51}; 
......

I am attaching the .geo file Attachment 40247

The gmshToFoam output is:

Code:

...
Mapping region 2 to Foam patch 0
Mapping region 1 to Foam patch 1
Mapping region 4 to Foam patch 2
Mapping region 5 to Foam patch 3
Mapping region 3 to Foam patch 4
Cells:
    total:0
    hex  :0
    prism:0
    pyr  :0
    tet  :0

--> FOAM FATAL IO ERROR: 
No cells read from file "naca5012_step3_structured.msh"
Does your file specify any 3D elements (hex=5, prism=6, pyramid=7, tet=4)?
Perhaps you have not exported the 3D elements?
...

yrganiri · June 19, 2015, 12:45

Ok, so now the checkMesh fails (when I use transfinite)

Code:

Checking geometry...
    Overall domain bounding box (-7.07107 -5 0) (5 5 1)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (1.63561e-17 9.81367e-18 -1.21481e-14) OK.
 ***High aspect ratio cells found, Max aspect ratio: 2729.23, number of cells 396
  <<Writing 396 cells with high aspect ratio to set highAspectRatioCells
    Minimum face area = 1.11556e-05. Maximum face area = 0.26532.  Face area magnitudes OK.
    Min volume = 1.11556e-05. Max volume = 0.0248775.  Total volume = 114.187.  Cell volumes OK.
    Mesh non-orthogonality Max: 88.9723 average: 40.767
   *Number of severely non-orthogonal (> 70 degrees) faces: 10057.
    Non-orthogonality check OK.
  <<Writing 10057 non-orthogonal faces to set nonOrthoFaces
    Face pyramids OK.
    Max skewness = 2.08422 OK.
    Coupled point location match (average 0) OK.

Failed 1 mesh checks.

It works wonderfully if I comment all the transfinite lines and just let gmsh do its meshing work.

Quote:

Originally Posted by hk318i

I had a quick look

Code:

Physical Volume("internal") = {50,52,54,55,53,51};

This definition is wrong because you don't have these volumes.

It should be

Code:

Physical Volume("internal") = {1,2,3,4,5,6};

Try it again and see if you have another problem.

hk318i · June 19, 2015, 12:54

It isn't easy to get the right mesh from the first trial. You can check the location of these high aspect ratio cells in paraView

makayasa · June 23, 2015, 14:08

Hello all. After converting gmsh to foam and I run , why the results in the show is not like the one in the tutorial ? I run simplefoam for airfoil2d case . Location of faults where ? How do I fix it ? This is my final project. Please advise. Thank you very much

yrganiri · June 23, 2015, 15:20

Quote:

Originally Posted by makayasa

Hello all. After converting gmsh to foam and I run , why the results in the show is not like the one in the tutorial ? I run simplefoam for airfoil2d case . Location of faults where ? How do I fix it ? This is my final project. Please advise. Thank you very much

Did you properly edit the 0/p 0/U ... and system/controlDict files with the same patch names as your mesh? Look at this example: https://community.dur.ac.uk/g.l.ingr...torial2012.pdf

hk318i · June 23, 2015, 15:28

It looks like the initial conditions, zero time.

bfigueroae · November 4, 2015, 14:16

Quote:

Originally Posted by MadsR

Thanks for the kind words

I made it some years ago - it has its flaws I am sure, but seems to be used quite a bit. You are of course most welcome to send me feedback.

Mads

hi MadSr. How do I cite http://hvirvel.dk/airfoilmesher/ (in a PhD thesis) ?

elmo555 · March 15, 2018, 10:56

Quote:

Originally Posted by MadsR

Just to clarify: there is nothing to download from http://hvirvel.dk/airfoilmesher/ . You just upload your airfoil x,y data and you get a blockMeshDict thrown back in your face

Mads

Hey Mads,

I just tried to use your mesher with default settings (also no airfoil data file), and unfortunately the generated blockMeshDict seems to be broken:

Code:

	Basic statistics
		Number of internal faces : 4
		Number of boundary faces : 16
		Number of defined boundary faces : 16
		Number of undefined boundary faces : 0
	Checking patch -> block consistency



--> FOAM FATAL ERROR: 
Block mesh topology incorrect, stopping mesh generation!

    From function void Foam::blockMesh::check(const Foam::polyMesh&, const Foam::dictionary&) const
    in file blockMesh/blockMeshCheck.C at line 228.

FOAM exiting

sibo · March 31, 2019, 18:38

Quote:

Originally Posted by MadsR

Just to clarify: there is nothing to download from http://hvirvel.dk/airfoilmesher/ . You just upload your airfoil x,y data and you get a blockMeshDict thrown back in your face

Mads

Hi Mads,

I'm wondering which format should we use for the coordinates file when generating a different airfoil?

Thanks!

sibo · March 31, 2019, 18:51

Quote:

Originally Posted by MadsR

Thanks for the kind words

I made it some years ago - it has its flaws I am sure, but seems to be used quite a bit. You are of course most welcome to send me feedback.

Mads

Hi Mads,

Firstly, thanks for the mesher you provided. I'm just wondering when we submit the airfoil coordinates, which format should we use?
Because I tried .dat, .txt and .rtf, they don't work.

Thanks a lot for the help!
Sincerely

sibo · April 1, 2019, 09:48

Hi Niels,

I'm wondering which format should we use when submitting a file?

Thanks a lot!

June 19, 2015, 12:21		#21
yrganiri New Member Romania Join Date: Dec 2014 Posts: 5 Rep Power: 11	Thank you for the help. I have tried exactly that but I cannot make gmshToFoam to work with what I have and I really don't know what I'm doing wrong. So, I am using the data points of RAE2822 and surround it with a C-type grid. It looks like this: Selection_139.png Now, my problem is that in order to make it look like that, I used many line loops and plane surfaces and I don't know how to name the physical surfaces: Code: Physical Surface("back") = {1042,1020,1064,1108,1125,1086}; Physical Surface("front") = {50,52,54,55,53,51}; ...... I am attaching the .geo file naca5012_step3_structured.txt The gmshToFoam output is: Code: ... Mapping region 2 to Foam patch 0 Mapping region 1 to Foam patch 1 Mapping region 4 to Foam patch 2 Mapping region 5 to Foam patch 3 Mapping region 3 to Foam patch 4 Cells: total:0 hex :0 prism:0 pyr :0 tet :0 --> FOAM FATAL IO ERROR: No cells read from file "naca5012_step3_structured.msh" Does your file specify any 3D elements (hex=5, prism=6, pyramid=7, tet=4)? Perhaps you have not exported the 3D elements? ...

June 19, 2015, 12:54		#24
hk318i Senior Member Hassan Kassem Join Date: May 2010 Location: Germany Posts: 242 Rep Power: 17	It isn't easy to get the right mesh from the first trial. You can check the location of these high aspect ratio cells in paraView yrganiri likes this. __________________ @HIKassem \| HassanKassem.me

June 23, 2015, 15:28		#27
hk318i Senior Member Hassan Kassem Join Date: May 2010 Location: Germany Posts: 242 Rep Power: 17	It looks like the initial conditions, zero time. __________________ @HIKassem \| HassanKassem.me

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