simulating 2D airfoil mesh in CFX

iffy · February 4, 2011, 05:37

Hi,
I need to calculate boundary layer characteristics for 2D airfoil. For this I made 2D mesh in ICEM CFD (exactly following Simon's tutorial). As CFX cannot handle 2D so I tried to convert it to 3D. I have read previous threads regarding how to do this. I have tried following 2 ways.
1) converting mesh file into Fluent output file. This way works to some extent but when I open this fluent mesh file into CFX, I cannot see some of the boundaries in CFX. I defined inlet, outlet, wall, top, bottom etc in ICEM CFD and when I open mesh file in CFX I can only see some of the boundaries there not all of them. Can anyone here has some idea about the reason for this and how to handle this?
2) I also tried extruding the 2D mesh by one cell to make it 3D. Although I define the curves in the parts which I want them as boundaries (the curves are associated to the edges) but still in CFX, I cannot see any boundaries where I can put the bocos. Can anyone knows something about this.
I will really any suggestion/advice regarding this.

Regards,
Irfan

saisanthoshm88 · February 4, 2011, 07:15

Well this question has been asked for a number of times on the forum before. you need to check the associations made once again because the line elements are generated only on those edges which are associated to the geometry you might have made the associations correctly in the begining but there can be some disassociations occuring when you do operations like split edges etc.., so to be sure of the associations have a look at the line elements before exporting the mesh just turn on the line elements but turn off the shell elements in the model tree to do that.

vmlxb6 · March 3, 2011, 03:59

Are you following the tutorial on you tube ???? Then you must be making a silly mistake here or there ??????? I have tried it and it works well.

lenovosk · March 8, 2011, 11:35

I agree with saisanthoshm88.

iffy · March 9, 2011, 02:53

Hi Santhosh, vmlxb6 & Lenovosk:

Thank you for your replies and useful suggestions. I managed to solve this problem. There was some problem with the geometry association as Santhosh pointed out.
But now I come across another problem: I want to determine laminar to turbulent transition for an airfoil for which I need the mesh to be orthogonal. Somehow I could not make the mesh perfectly orthogonal. I have tried smoothing option but it always distorts the mesh.
I will appreciate if anyone here can provide some suggestion to resolve this.

Regards,

Irfan

vmlxb6 · March 9, 2011, 03:10

One way I know is to specify the first layer distance from the boundary wall. It also makes sure that the first set of elements or BL is orthogonal. In the tutorial provided by Simon on you tube, When he does smoothing, he specifies the orthogonal distance first.

Am I on the right track ??? Is this what you wanted ???

iffy · March 9, 2011, 03:53

Actually I have tried this option, it works to some extent. It makes first layer in the boundary layer region orthogonal but it distorts the mesh everywhere around. I am looking for some other option/function in ICEM.

JEEVANSADALGE@GMAIL.COM · January 24, 2017, 03:05

i am also facing the same problem while doing meshing to my 2d airfoil
can anyone suggest the solution??

orthogonal elements to airfoil

February 4, 2011, 05:37	simulating 2D airfoil mesh in CFX	#1
iffy New Member Irfan Join Date: Jan 2011 Location: Netherlands Posts: 16 Rep Power: 15	Hi, I need to calculate boundary layer characteristics for 2D airfoil. For this I made 2D mesh in ICEM CFD (exactly following Simon's tutorial). As CFX cannot handle 2D so I tried to convert it to 3D. I have read previous threads regarding how to do this. I have tried following 2 ways. 1) converting mesh file into Fluent output file. This way works to some extent but when I open this fluent mesh file into CFX, I cannot see some of the boundaries in CFX. I defined inlet, outlet, wall, top, bottom etc in ICEM CFD and when I open mesh file in CFX I can only see some of the boundaries there not all of them. Can anyone here has some idea about the reason for this and how to handle this? 2) I also tried extruding the 2D mesh by one cell to make it 3D. Although I define the curves in the parts which I want them as boundaries (the curves are associated to the edges) but still in CFX, I cannot see any boundaries where I can put the bocos. Can anyone knows something about this. I will really any suggestion/advice regarding this. Regards, Irfan

February 4, 2011, 07:15		#2
saisanthoshm88 Senior Member --------- Join Date: Oct 2010 Posts: 303 Rep Power: 17	Well this question has been asked for a number of times on the forum before. you need to check the associations made once again because the line elements are generated only on those edges which are associated to the geometry you might have made the associations correctly in the begining but there can be some disassociations occuring when you do operations like split edges etc.., so to be sure of the associations have a look at the line elements before exporting the mesh just turn on the line elements but turn off the shell elements in the model tree to do that. __________________ Best regards, Santhosh. Last edited by saisanthoshm88; February 6, 2011 at 23:59.

March 9, 2011, 03:10	@ iffy	#6
vmlxb6 Senior Member Ugly Kid Joe Join Date: Aug 2010 Posts: 193 Rep Power: 15	One way I know is to specify the first layer distance from the boundary wall. It also makes sure that the first set of elements or BL is orthogonal. In the tutorial provided by Simon on you tube, When he does smoothing, he specifies the orthogonal distance first. Am I on the right track ??? Is this what you wanted ???

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March 3, 2011, 03:59		#3
vmlxb6 Senior Member Ugly Kid Joe Join Date: Aug 2010 Posts: 193 Rep Power: 15	Are you following the tutorial on you tube ???? Then you must be making a silly mistake here or there ??????? I have tried it and it works well.

March 8, 2011, 11:35		#4
lenovosk New Member Join Date: Mar 2011 Posts: 1 Rep Power: 0	I agree with saisanthoshm88.

March 9, 2011, 02:53		#5
iffy New Member Irfan Join Date: Jan 2011 Location: Netherlands Posts: 16 Rep Power: 15	Hi Santhosh, vmlxb6 & Lenovosk: Thank you for your replies and useful suggestions. I managed to solve this problem. There was some problem with the geometry association as Santhosh pointed out. But now I come across another problem: I want to determine laminar to turbulent transition for an airfoil for which I need the mesh to be orthogonal. Somehow I could not make the mesh perfectly orthogonal. I have tried smoothing option but it always distorts the mesh. I will appreciate if anyone here can provide some suggestion to resolve this. Regards, Irfan

March 9, 2011, 03:53		#7
iffy New Member Irfan Join Date: Jan 2011 Location: Netherlands Posts: 16 Rep Power: 15	Actually I have tried this option, it works to some extent. It makes first layer in the boundary layer region orthogonal but it distorts the mesh everywhere around. I am looking for some other option/function in ICEM.

January 24, 2017, 03:05		#8
JEEVANSADALGE@GMAIL.COM New Member JEEVAN Join Date: Nov 2016 Location: bangalore,india Posts: 4 Rep Power: 9	i am also facing the same problem while doing meshing to my 2d airfoil can anyone suggest the solution?? orthogonal elements to airfoil