# curve in airfoil

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 October 13, 2014, 01:17 curve in airfoil #1 Senior Member   Aja Join Date: Nov 2013 Location: Hungary Posts: 375 Rep Power: 6 Hi Friends I have a two-dimensional airfoil got into Gambit. I wanted to know how to give it a curve? Wells turbine is the subject of the my Thesis. Note the curvature of the tip in the image below: Thanks for your help

 October 13, 2014, 01:36 #2 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,186 Rep Power: 33 display what you already have in Gambit aja1345 likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 13, 2014, 12:08
#3
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Aja
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Quote:
 Originally Posted by -mAx- display what you already have in Gambit
Hi dear friend

Thanks .... note the following:

 October 13, 2014, 12:15 #4 Senior Member     Daniele Join Date: Oct 2010 Location: Italy Posts: 995 Rep Power: 17 I would: - merge edges; - create the face from merged edges; - create a volume from sweeping the created face (+z direction); - copy/rotate the volume aroung the central axis; - create the central cilinder volume; - merge all the volumes; - if you need to "curve" external surfaces, create a cilinder volume and cut the blades; - create external volume (air volume); - subtract internal (solid) volume from external (air) volume. -mAx- and aja1345 like this.

October 13, 2014, 14:07
#5
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Aja
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Quote:
 Originally Posted by ghost82 I would: - merge edges; - create the face from merged edges; - create a volume from sweeping the created face (+z direction); - copy/rotate the volume aroung the central axis; - create the central cilinder volume; - merge all the volumes; - if you need to "curve" external surfaces, create a cilinder volume and cut the blades; - create external volume (air volume); - subtract internal (solid) volume from external (air) volume.
hi dear friend

Thank you.
But as the following:

modelling:

We use the periodic boundary condition

now,What should I do?

 October 13, 2014, 14:21 #6 Senior Member   Aja Join Date: Nov 2013 Location: Hungary Posts: 375 Rep Power: 6 Sorry,I have an other question: Assuming that it is available vertexes of airfoil. How to put vertexes of airfoil on the Cylinder(Cylinder that must be cut)? Because the beginning, the points of airfoils are no curvature. I'm confused!!!!!

October 14, 2014, 00:51
#7
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Maxime Perelli
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Quote:
 Originally Posted by ghost82 I would: - merge edges; - create the face from merged edges; - create a volume from sweeping the created face (+z direction); - copy/rotate the volume aroung the central axis; - create the central cilinder volume; - merge all the volumes; - if you need to "curve" external surfaces, create a cilinder volume and cut the blades;
--> from here you get your rotor as solid

Quote:
 Originally Posted by ghost82 -create external volume (air volume); - subtract internal (solid) volume from external (air) volume
--> you extract the fluid domain. The height of your external volume must be 12L, and move it to its right place
From here you have a full modell.
If you want to work with periodicity, you can split the model

Quote:
 Originally Posted by amir star Sorry,I have an other question: Assuming that it is available vertexes of airfoil. How to put vertexes of airfoil on the Cylinder(Cylinder that must be cut)? Because the beginning, the points of airfoils are no curvature. I'm confused!!!!!
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In memory of my friend Hervé: CFD engineer & freerider

October 14, 2014, 02:05
#8
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Aja
Join Date: Nov 2013
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Quote:
 Originally Posted by -mAx- --> from here you get your rotor as solid --> you extract the fluid domain. The height of your external volume must be 12L, and move it to its right place From here you have a full modell. If you want to work with periodicity, you can split the model I didn't get your point
If u Imagine that I have the vertices coordinates related to airfoil, how can i fit or put the vertices on the rotor hob in order to coincide them.
I don't have any idea about it the software I used is Gambit ver.2.4

 October 14, 2014, 02:50 #9 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,186 Rep Power: 33 As ghost82 mentionned, you can merge all your tiny edges from airfoil, except both designing trailing edge. Doing that you will still have one vertex (sharp angle from trailing edge) You are also free to choose another one vertice: you can for example use the split edge tool: https://www.sharcnet.ca/Software/Gam...eom_edge_split aja1345 likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 14, 2014, 04:43
#10
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Daniele
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Quote:
 Originally Posted by amir star Sorry,I have an other question: Assuming that it is available vertexes of airfoil. How to put vertexes of airfoil on the Cylinder(Cylinder that must be cut)? Because the beginning, the points of airfoils are no curvature. I'm confused!!!!!
Hi,
here is what I mean:
When you merge the 2 volumes, after sweeping the airfoil, you will have the airfoil edge automatically projected to the cylinder (bottom-left image).
If you need to curve the airfoil create a new cilinder (red dotted) and cut the 3d blade, then delete the more external volume (black dotted).
Attached Images
 cfd.jpg (25.8 KB, 9 views)

 October 15, 2014, 03:01 thank #11 Senior Member   Aja Join Date: Nov 2013 Location: Hungary Posts: 375 Rep Power: 6 hi my dear friends. I can almost design Primary model with your guidance s but for merge edge I face a problem. Edge merge method don't understand.how merge edge? for this reason,i am doing edge and faces without merge but for Construct blade volume i face a problem and blade volume don't Construct correctly,attention to bellow image: According to the following image, For merge,two Later edge don't consider but get following error: too,total edges consider but again get following error: vertexes of airfoil figure Before construct volume: vertexes of symmetrical airfoil: edge and faces of symmetrical airfoil: Blade figure Before construct volume: figure of modeling: Thank you for allocating your time.

 October 15, 2014, 04:02 #12 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,186 Rep Power: 33 follow instructions from ghost82: work only with volumes (not surfaces) aja1345 likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 15, 2014, 06:00
#13
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Daniele
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Merge edges!
see here:
https://www.sharcnet.ca/Software/Gam...ide/mg0203.htm

Default is split edge, so right click on the split edge button to select merge edges, select 2 edges at a time and merge them.
I suggest to leave 2 vertices to easily mesh geometry (see picture).

PS: I'm automatically updated when somebody reply to this thread so no need to send private messages :P
Attached Images
 cfd.png (1.6 KB, 3 views)

 October 15, 2014, 08:37 #14 Senior Member   Aja Join Date: Nov 2013 Location: Hungary Posts: 375 Rep Power: 6 hi,thanks In some cases when I do merge some edges by the chance it merges and virtual edge is created instead of the real edge. is there any rule for merging that i don't follow it or these kind of virtual edges don't create any problem in further processing steps? virtual edges: thank for your helps.

 October 20, 2014, 15:00 #15 Senior Member   Aja Join Date: Nov 2013 Location: Hungary Posts: 375 Rep Power: 6 Dear Friends, First, I would like to thank you for all your help and inform you that I have finally made my intended model. In my model, I want to make the upper airfoil cord bigger than the buttom one. I would appreciate it if you could kindly give me your advice. if you could send me a visual, H would be thankful. Best, Amir

 October 21, 2014, 01:20 #16 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,186 Rep Power: 33 if you modify the design of your airfoil, you will have to redo everything. But you can use your previous journal file to "automatically" rebuild your geometry. https://www.sharcnet.ca/Software/Gam...#menu_file_run if you only want to extend your domain, the sweep tool should be suitable aja1345 likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 21, 2014, 16:25
#17
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Aja
Join Date: Nov 2013
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Quote:
 Originally Posted by -mAx- if you modify the design of your airfoil, you will have to redo everything. But you can use your previous journal file to "automatically" rebuild your geometry. https://www.sharcnet.ca/Software/Gam...#menu_file_run if you only want to extend your domain, the sweep tool should be suitable
hi,

thanks

Yes, but I my problem is making the blade.
Dash line is for previous model.
New model is red lines that I do not know that model.

In the meantime I've deleted the journal file and have the file (dbs).
Until now I did not work with journal file.

From First modeling, but how do I create blade?

Such post #10 with pictures to explain me,I would be thankful.

Thank you for allocating your time.

October 22, 2014, 00:52
#18
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Maxime Perelli
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Quote:
 Originally Posted by amir star From First modeling, but how do I create blade?
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In memory of my friend Hervé: CFD engineer & freerider

 October 22, 2014, 03:07 #19 Senior Member   Aja Join Date: Nov 2013 Location: Hungary Posts: 375 Rep Power: 6 hi my dear friend i have created the blade with sweep tool, and so with volume split tool by face. Procedure is as follows: sweep airfoil(face): create new cylinder: blade volume subtract volume 6: create edges for Faces: created faces: volume split tool by created faces: continue.....

 October 22, 2014, 03:08 #20 Senior Member   Aja Join Date: Nov 2013 Location: Hungary Posts: 375 Rep Power: 6 deleted volumes: Thank you for allocating your time. I really do not know what to do for the new model.Now Here, I do not think the sweep tool is efficient( in Third picture Previous post). best, Amir

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