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 April 12, 2005, 07:55 Hi everybody, i've written #1 Senior Member   Markus Hartinger Join Date: Mar 2009 Posts: 102 Rep Power: 8 Hi everybody, i've written a calculator for the grading in the blockMesh format some time ago. It relates length, number of cells, total expansion ration, cell-to-cell expansion ratio, start cell size and end cell size. Given the length and any two of the other, the remaining values are calculated. It's a little programm, but I found it myself useful generating meshes with blockMesh. If someone improves it, let me know MeshSpace.tar.gz regards Markus eac, shadowfax, m.goudarzi and 1 others like this.

 April 12, 2005, 09:36 Actually, the grading factor i #2 Senior Member   Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,763 Rep Power: 21 Actually, the grading factor in blockMesh is defined as the ratio of the last to first cell size, which is much better behaved that defining the number of cells and the geometric expansion ratio. I suppose we have both done the same thing :-) Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

 December 19, 2006, 01:09 Hi Markus, Thanks for the u #3 Senior Member   Srinath Madhavan (a.k.a pUl|) Join Date: Mar 2009 Location: Edmonton, AB, Canada Posts: 699 Rep Power: 12 Hi Markus, Thanks for the utility. I found it very useful; esp. to find out the number of cells when one knows the start and end cell sizes in addition to the length. I had to edit the Makefile to remove the reference to the bin subdirectory which does not exist. A sample of the utility usage is shown below for those who need to know how to use it: madhavan@karmayug:~/MeshSpace$./MeshSpace ds de 0.58 0.000625 0.003125 Meshspace results by Markus.Hartinger@imperial.ac.uk : Length L : 0.58 Number of cells n : 373 Total expansion ratio r : 5 Cell-to-cell expansion k : 1.00434 Start cell size ds: 0.000625305 End cell size de: 0.00312652 madhavan@karmayug:~/MeshSpace$ lav likes this.

 February 6, 2007, 05:08 Hi Markus Would you please #4 New Member   Armin Hosseinian Join Date: Mar 2009 Location: Perth, Western Australia, Australia Posts: 17 Rep Power: 8 Hi Markus Would you please tel me how your calcualtor works? i Couldent open that. Cheers

 August 26, 2008, 18:29 I get this error with gcc 4.3. #5 Senior Member   Srinath Madhavan (a.k.a pUl|) Join Date: Mar 2009 Location: Edmonton, AB, Canada Posts: 699 Rep Power: 12 I get this error with gcc 4.3.1 when running make. Any idea what is wrong? g++ -g -c MeshSpace.cpp MeshSpace.cpp: In function 'int main(int, char**)': MeshSpace.cpp:35: error: 'exit' was not declared in this scope MeshSpace.cpp:38: error: 'atof' was not declared in this scope make: *** [MeshSpace.o] Error 1

 September 1, 2008, 16:25 Problem solved. It was just a #6 Senior Member   Srinath Madhavan (a.k.a pUl|) Join Date: Mar 2009 Location: Edmonton, AB, Canada Posts: 699 Rep Power: 12 Problem solved. It was just a question of adding: #include to MeshSpace.cpp and TEdgeSpace.cpp

 July 21, 2010, 09:36 #7 Member     Alessandro Join Date: Nov 2009 Posts: 67 Rep Power: 7 Sorry, which is the problem?? 5:45 ale@alien:~/MeshSpace\$ make g++ -g -c MeshSpace.cpp g++ -g -c TEdgeSpace.cpp g++ -g -o bin/MeshSpace MeshSpace.o TEdgeSpace.o /usr/bin/ld: cannot open output file bin/MeshSpace: No such file or directory collect2: ld returned 1 exit status make: *** [MeshSpace] Errore 1 __________________

July 22, 2010, 07:37
#8
Senior Member

David Boger
Join Date: Mar 2009
Location: Penn State Applied Research Laboratory
Posts: 146
Rep Power: 8
Quote:
 Originally Posted by 83_Ale_83 Sorry, which is the problem??
If you read back a few posts, Srinath has already given the answer to this problem (and the next one you'll encounter). Delete bin/ from the Makefile, and include <cstdlib> in both .cpp files.
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David A. Boger

July 22, 2010, 08:04
#9
Member

Alessandro
Join Date: Nov 2009
Posts: 67
Rep Power: 7
Quote:
 Originally Posted by dab143psuedu If you read back a few posts, Srinath has already given the answer to this problem (and the next one you'll encounter). Delete bin/ from the Makefile, and include in both .cpp files.
What a useless question I have done, I have missed the post
Thank you
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 September 4, 2010, 17:40 Stupid question.. #10 Senior Member   Nilesh Rane Join Date: Apr 2010 Posts: 122 Rep Power: 7 How to give the arguments to the program??? I didnt get it.. Sorry for this stupid question. __________________ Imagination is more important than knowledge..

September 6, 2010, 03:19
#11
Member

Alessandro
Join Date: Nov 2009
Posts: 67
Rep Power: 7
Quote:
 Originally Posted by nileshjrane How to give the arguments to the program??? I didnt get it.. Sorry for this stupid question.

Look at the third post; it's just an example
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 September 6, 2010, 05:44 #12 Senior Member   Nilesh Rane Join Date: Apr 2010 Posts: 122 Rep Power: 7 Oh yes...i just overlooked it..i was trying meshspace value ds value de value...etc __________________ Imagination is more important than knowledge..

 December 22, 2010, 06:02 Broken Link? #13 Member   P.A. Join Date: Mar 2009 Location: Germany Posts: 47 Rep Power: 8 Hi, I cannot download the .tar.gz file. All I get is a short html file saying that the file I was looking for was not found on the server. This is saved with a .unk file extension. Using wget http://... brings the same result. Can anybody shed some light on this? Or send me the file via email to pascal \at\ pascal-anschau \dot\ de? Thanks in advance! Cheers, Pascal.

May 15, 2011, 12:14
#14
Member

Join Date: May 2010
Posts: 44
Rep Power: 7
Quote:
 Originally Posted by armin_h Hi Markus Would you please tel me how your calcualtor works? i Couldent open that. Cheers
I think it solves the equations I posted there: edge sizing control--Calculate cell-to-cell expansion rate from bias factor

Just rename the downloaded file to "MeshSpace.tar.gz", extract it, then it should work.

June 16, 2011, 13:51
#15
Member

Alex
Join Date: Jun 2010
Location: Planet Earth
Posts: 43
Rep Power: 7
Quote:
 Originally Posted by boger If you read back a few posts, Srinath has already given the answer to this problem (and the next one you'll encounter). Delete bin/ from the Makefile, and include in both .cpp files.
Thanks. This tools is just what I was looking for to mesh my boundary layer! Good show.

 August 17, 2011, 12:31 #16 New Member   Pam Join Date: Feb 2011 Posts: 15 Rep Power: 6 Hi Srinath, I am new to OpenFoam. I need to create a mesh for channel with non linear mesh. My node spacing is 12% increment for first 20 nodes near wall and 1.5 times viscous length scale and then 8% near the cwnter line and same on the otherside of the center line too.. I am confused how do I can take expansin ration? Thanks in advance, Prameela. __________________ Pam

 August 17, 2011, 13:27 #17 Member   Alex Join Date: Jun 2010 Location: Planet Earth Posts: 43 Rep Power: 7 Hi Pam, I would suggest first learning how to use blockMesh utility with openFOAM. You will need to separate the mesh into separate blocks for each grading. First do a couple of the tutorials here to learn Then use hartinger's tool to specify the grading based on your requirement. Good luck.

 February 27, 2012, 05:01 Blockmesh #18 Senior Member   kumar Join Date: Nov 2011 Posts: 115 Rep Power: 5 Dear Foamers, i have xyz coordinates(that is model have 33 coumns and 225 rows in .csv file format) how i import and create blockmesh andbody have idea please let me know. Thanks for the answer in advance!

 April 8, 2012, 09:32 #19 New Member   Kirill Cherniy Join Date: Apr 2012 Posts: 3 Rep Power: 5 first: are these coordinates of block vertices? second: if so u can easyli write converter that will pull vertices of that file and create blocks, faces and edges. if not that is not so easy. Hint: remember that spline edges use mirror of last point for approxymation of y' in last point.

 April 9, 2012, 02:10 blockmesh-flapping wing #20 Senior Member   kumar Join Date: Nov 2011 Posts: 115 Rep Power: 5 Dear Slackware_user, thanks for your reply first: these are the 3Dmodel coordinates generated in matlab,i have xyz coordinates of that model.for example generally people goes for cad model, same thing of that cad model but thing is i have coordinates, in matlab(that is model have 33 coumns and 225 rows xyz coordinates in .csv file format)how i can go for blockmesh. Thanks for the answer in advance!

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