Structured Hexa Mesh on Wing
 

I am looking for the help regarding structured hexa mesh in ICEM CFD on the simple wing body but till yet output is zero. So I kindly request experienced users like Far, Simon, Energy,Stuart or any other person to kindly help me in this. All I know about the structured meshing is about the meshing tutorial of aerofoil created by Simon, so my knowledge is very limited and looking forward for some good help from you guys. Thanks in advance
Regards

Far I have started the new topic, kindly comment....

some pics and tin file please

I don't have the tin file at home,its at my workplace but my geometry is very simple. Rectangular wing made of Naca 0015 airfoil, 1.7 feet chord and 5.59 feet semi-span, no fuselage. I only want to analyse the semi span....

Please reply here Far, Simon, Stuart....

You follow the series of video tutorials for a 2D airfoil by Simon.

http://www.youtube.com/watch?v=tYrbS...ACDC3F0407C92C

Then extrude in the z-direction or whatever your semi0span direction to convert it to 3D.

Do something then post it on the forum. I feel nobody will do your work. People only guides you.

Best of Luck.

yah Ali i know and i have mentioned in my 1st post that i know how to generate structured mesh around aerofoil...but how to extrude that in the 3rd-dimension?? its not easy as it can be said in just 1 sentence...if you know about this then kindly help...

post a tin file and I will take a look on it and suggest you the blocking.

ok Far I have saturday and sunday off...I will post my tin file tomorrow

I check the airfoil blocking and tin file in my database (if found) and shall post today the process of extrude as suggested by Hybrid.

Blocking --> Create Block --> Extrude Face

Thanks Far it will be of grreat help to me.
Hybrid...I am new on ICEM CFD, in 2D blocking we dont have have mesh on the aerofoil itself but extruding the aerofoil in 3rd dimension has a wing tip face which also needs to be meshed, so by simply extruding the aerofoil mesh in z-direction how can we get the mesh around the wing??

http://www.mediafire.com/file/ux31w3rtl4szto2/thurs wing.tin
here is my tin file Far...I shall be very thankful to you for the help, thanks in advance.
Regards

Far I am waiting for your help, kindly comment

no one is replying here....please Far,Simon and co..........

try something and post you related problem!!

worked on the 3D wing. But having problem in creating the o block around wing due to use of collapse command for sharp trailing edge. Shall upload video clip on Monday. May be some else know the solution of this problem.

Thanks a lot Far for your reply, it will be great help from your side, may be Simon will resolve that issue....

First three Figs show the blocking after merging for sharp trailing edge and use of y-block command. Fourth Fig. indicate that the o-block is not successful for unknown reasons.

Domain is changed into rectangular shape. You can use the round far field at inlet, in this case blocking strategy would be different, similar to Simon's youtube tutorial on airfoil.

Files are also attached

http://img43.imageshack.us/img43/3809/wing1.png
http://img543.imageshack.us/img543/4581/wing2.png
http://img171.imageshack.us/img171/8408/wing3.png
http://img542.imageshack.us/img542/597/wing4.png

Method 2
 

Method 2

http://www.4shared.com/rar/qXCmda1T/file.html

In this method, O block around wing is created first (blocks collapsed in previous step at trailing edge), then tip block is split into two parts one for leading edge and one for trailing. For trailing edge block with 3 edges, Y-block is inserted. For the leading edge block, O-block is applied. See attachments and Figs.

Now working on method 3, that is not to use the collapse block command and simply creating O-block around air foil assuming trailing edge is also round.

http://img72.imageshack.us/img72/1854/wing5.png
http://img204.imageshack.us/img204/373/wing6.png
http://img21.imageshack.us/img21/2342/wing7.png
http://img42.imageshack.us/img42/416/wing8.png
http://img217.imageshack.us/img217/8526/wing9.png

Quality
 

Quality is good enough (min 0.64) and can be improved further by adjusting the blocking.

http://img201.imageshack.us/img201/1170/wing10.png

Method2_Modified
 

There is little modification in method 2 >>>> Method 2 - Modified

Instead of O-Block in the tip region in leading edge block, this time I have used C-topology(selecting two rear edges).

http://img138.imageshack.us/img138/1730/wing11.png
http://img16.imageshack.us/img16/7959/wing12.png
http://img88.imageshack.us/img88/6045/wing13.png

Method 3
 

Method 3

Y-blocking is not needed for this topology scheme.

Blocked collapse or node merge was not used.

O-grid is created around wing and inside wing tip block. See attached files and Pics.

http://img840.imageshack.us/img840/2648/wing15.png
http://img138.imageshack.us/img138/319/wing16.png
http://img843.imageshack.us/img843/6070/wing17.png
http://img3.imageshack.us/img3/6218/wing18.png
http://img714.imageshack.us/img714/4453/wing19.png
http://img252.imageshack.us/img252/5803/wing20.png
http://img7.imageshack.us/img7/4152/wing21.png
http://img42.imageshack.us/img42/1985/wing22.png

Far thank you very much for taking out time and doing this stuff for me but as I have told you I have no experience at all in blocking strategies. If you can create a tutorial or at least a word document narrating the steps for creating the blocks and setting the mesh parameters then it will really help me and I shall be very thankful to you for this. I know I am asking for a bit more but as I have already told you that I have no experience at all in this and no one around me knows about this. Thanks in advance.

Thanks Far for all your hard work on this one... I have been busy at work lately, and working long hours.

There are several ways to handle a 3D wing. This one's key features are a sharp trailing edge (which suggests a C Grid) and a flat wing tip, which is most easily captured with (Blocking => Create => 2D to 3D).

Start with a 2D blocking... But because you will need to keep the flow volume past your wing tip, you also need to mesh inside the airfoil. The topology Far showed works well, or if you can handle wedges in your model, you could just keep the very simple collapsed block you got from collapsing the blocks behind the trailing edge, then add the Ogrid to the front inner block of the airfoil.

Then go to Create Blocks => 2D to 3D and choose the "by translation" option. Put in the width of your box and apply.

Then go and "delete" the blocks that should end up inside the airfoil (or put then in a solid blocking material).

Associate all the edges with the 3D curves, set up edge parameters, etc.

Done.

Far kindly explain the method-2 in detail, i want to know how you have split- ed the wing tip block and inserted O-grid at leading edge and Y-block at trailing edge?? by which method you have inserted Y-block at the trailing edge?? and you have split-ed the main block in method-2 as you have explained in your video tutorial....am i right??

first split tip block (across all other blocks as well) and then

1. For leading edge block >>> go to oblock panel and insert the oblock and select two faces parallel to tip face.

2. For trailing edge block >>>> go to edit block and convert into Y-block.

Yes

Finally, I concluded that for wing with sharp trailing edge, the best domain is circular (hemisphere in 3d) shape at inlet and rectangular at outlet (cylinder)

I am still confused how to implement the method no.2, I am going to explain my understanding, kindly direct me where i will be wrong.
Method 2-O-grid around leading edge and Y-grid in the trailing edge
after splitting the main block using 2 points near the leading edge,edge to curve association fallowed by O-grid only around the wing(not around the wing tip block...am i right here?), then the block split behind the trailing edge fallowed by tip block split into leading edge and trailing edge blocks(where to split the tip block? at half chord?) and finally O-grid around leading edge block and Y-block around trailing edge block.
Few more questions......
1. In the tip region, Ogrid willbe created in the block or around the block?
2. Y-block will be inserted using vertex merge method or what method?
3. You said split the tip block across all other blocks....by "across all other blocks" you mean the block passing inside the wing also?

anyone please..........

I have almost learned the method 2 expect few steps...after splitting the tip block if the O-grid around the leading edge will be inserted then why we need to select the faces parallel to tip block? or I may be wrong here?? if yes then kindly direct me?

can you post the last few steps of your working? Where are you stuck up?

Also post .blk and .tin file.

My case is a bit different from the Naca 0015 wing case. Wing is not symmetric rather its cambered, so I decided to use method no.2 for blocking the geometry(O-grid around the block and Y-block in the tip block in the vicinity of trailing edge and O-block in the vicinity of leading edge).
I am explaining my effort in few steps so that you can figure out my mistake.....
1. 3D blocking, splitted the main block using the 2 points near the leading edge.
2. Necessary edge to curve association and vertex moved to form the block inside wing
3. Collapsed the block behind the trailing edge and vertex moved to fit the block inside wing
4. O-grid around the wing and tip block(0.1m block using absolute checked on)
5. Splitted the tip block(across the block inside wing) near the trailing edge

The work till step 5 is attached in post with the name "wing_hexa"
After this I am stucked up, I am trying to insert O-grid around the leading edge block(wing and tip block both) but not getting the blocking like as you did.
My wrong effort is attached in the post with name "wing_hexa_wrong"
I WANT TO KNOW....how you got the rounded block all around the wing and tip block and how you fitted the Y-block in the tip near trailing edge

Thanks in advance
Regards

have you seen my blocking files???

Your blocking was very confusing there were a lot of blocks. i couldn't follow it. When i get lost like that. i erase and redo everything. maybe you are in hurry to start simulation. i made a blocking for you. take a look at it. while simulating, you can come back to geometry and analyse what was wrong.
starting by initializing a block, splitting around airfoil.
then i create an o-grid inside that split, collapsed the block by merging vertices.
next split again the o-grid around your airfoil. you will then have two zones, one for leading edge and trailing edge. it is better to start by a small o-grid inside the leading edge, then you create the Y-grid for the trailing edge. after that come another y-grid for behind the airfoil. then you adjust vertices to get good quality
https://dl.dropbox.com/u/35161486/airfoil.png

ok as i understood, when you splitted the main block, you directly performed association ?
NO, when you split the main block, the new block you get shouldn't be associated to the wing, you have to split it one more time into another o'grid. then you will associate with the wing. don't think about splitting AROUND. you got it ?

Thanx Ali....i have a question
1. After the initial split, we will create Ogrid inside the wing block and tip block(tip block is the block extending from the tip in the z-direction) or we will create Ogrid around wing block and tip block? I am considering Ogrid inside block and around block are different things, am I right? Please explain this point in detail

oh you replied before me i just noticed it :p
yes exactly after the initial split i associated the edges to curves to get the block inside the wing...tell me what i have to do instead?? and you are talking about "you have to split it one more time into another o'grid"...I am not getting this, please explain it in more detail....I guess this is my problem where I am stuck up....

INSIDE.look at the picture below. the initial block gave the block in red.
After that i created an ogrid inside , which is the green one. i then applied association.
after that i splitted vertically, which is purple line.
then i created another ogrid INSIDE, which is orange.
Then finally transformed the block behind in ygrid

https://dl.dropbox.com/u/35161486/airfoil_steps.png