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-   -   [ICEM] Ahmed body Hexa mesh (with legs) (http://www.cfd-online.com/Forums/ansys-meshing/108657-ahmed-body-hexa-mesh-legs.html)

Far October 29, 2012 14:42

Ahmed body Hexa mesh (with legs)
 
Previously I showed the Ahmed's body mesh without legs. This time legs are also included. First o-grid is made around main body and then around two legs up to the road surface (bottom)

http://imageshack.us/a/img513/929/withlegs1.png

http://imageshack.us/a/img803/299/withlegs2.png

http://imageshack.us/a/img689/1497/withlegs3.png

http://imageshack.us/a/img22/5570/withlegs4.png

http://imageshack.us/a/img534/1426/withlegs5.png

http://imageshack.us/a/img703/6270/withlegs6.png

Far October 30, 2012 00:07

Video clip (50 minutes and voice is also included) and other necessary files are also available.

PSYMN November 5, 2012 15:11

Available where?

diamondx November 5, 2012 15:22

Far's channel : http://www.youtube.com/user/turboeng.../videos?view=0

PSYMN November 5, 2012 15:28

I figured I would ask just to get the link up on this thread ;)

Far November 5, 2012 22:04

Quote:

Originally Posted by PSYMN (Post 390403)
I figured I would ask just to get the link up on this thread ;)

Thankyou Simon. Here are the links to four videos on Ahmed body meshing and simulation.

http://www.youtube.com/watch?v=2baEa...4&feature=plcp

http://www.youtube.com/watch?v=A-xZx...FFBEC4&index=4

http://www.youtube.com/watch?v=0t2jh...FFBEC4&index=3

http://www.youtube.com/watch?v=oyfKS...FFBEC4&index=2

Link to youtube channel:

http://www.youtube.com/my_videos

Sixkillers November 6, 2012 03:04

Quote:

Link to youtube channel:
http://www.youtube.com/my_videos
I think the link might not be working ;)

Far November 6, 2012 04:48

Quote:

Originally Posted by PSYMN (Post 390401)
Available where?

The video for that particular case (with legs) is available in my PC:D but it is too big for the YouTube (600 mb). I can share it through dropbox or may be I try to get the low quality video and then upload it on the YouTube.

PSYMN November 6, 2012 05:38

The Links worked for me.

Also, I see that ANSYS inc's Tech page has "liked" Far's videos, so they are visible from there as well.

http://www.youtube.com/user/ANSYSTechTips

Thanks Far for contributing over 6 hours of video!

cfd seeker November 6, 2012 12:58

Far has contributed so much to this forum, he deserves to be the ADMIN of the page really

PSYMN November 6, 2012 13:06

Quote:

Originally Posted by cfd seeker (Post 390637)
Far has contributed so much to this forum, he deserves to be the ADMIN of the page really

Find him on Linked in and give him a recommendation that may pay off outside this forum...

I was about to provide a link, but that is not my place...

Instead, just do a google search for his email address and look for the linked in options... You will find his contact etc.

Anna Tian February 2, 2014 08:06

1 Attachment(s)
Quote:

Originally Posted by Far (Post 389165)
Previously I showed the Ahmed's body mesh without legs. This time legs are also included. First o-grid is made around main body and then around two legs up to the road surface (bottom)

http://imageshack.us/a/img513/929/withlegs1.png

http://imageshack.us/a/img803/299/withlegs2.png

http://imageshack.us/a/img689/1497/withlegs3.png

http://imageshack.us/a/img22/5570/withlegs4.png

http://imageshack.us/a/img534/1426/withlegs5.png

http://imageshack.us/a/img703/6270/withlegs6.png

Your fourth grids figure shows very large grids expansion ratio (volume of change) near the pillar? It looks like it is above 10. Usually the criteria for expansion ratio is below 5 or 6. Any justification of using large expansion ratio? It also shows up in the other regions in your other pictures. You have fine mesh to model the BL. Then you have a very sudden size change with very large grids expansion ratio to the neighboring grids.

Far February 2, 2014 08:23

Quote:

Originally Posted by Anna Tian (Post 472957)
Your fourth grids figure shows very large grids expansion ratio (volume of change) near the pillar? It looks like it is above 10. Usually the criteria for expansion ratio is below 5 or 6. Any justification of using large expansion ratio? It also shows up in the other regions in your other pictures. You have fine mesh to model the BL. Then you have a very sudden size change with very large grids expansion ratio to the neighboring grids.

That was a very quick mesh and not meant for simulation. The purpose only is to show the blocking strategy in ICEM CFD.

Anna Tian February 2, 2014 08:32

Quote:

Originally Posted by Far (Post 472961)
That was a very quick mesh and not meant for simulation. The purpose only is to show the blocking strategy in ICEM CFD.

Ok. Thank you a lot for your posts on Ahmed body simulation. You show a good practice for the vehicle aerodynamics modeling. These information are very helpful to me.

We know that CFD could reach very good correspondence with experimental data for Ahmed body. I'm wondering is this good match kind of coincidence or we can say nowadays generally CFD with RANS model is already able to well model the blunt body drag like for other vehicle geometries?

Far February 2, 2014 08:49

Due to high power of computer speed and memory, we can now run fine meshes on routine which was previously only possible at big institute/laboratories. In addition to that solver algorithms and flow schemes are also improving at rapid rate. So now a days we can resolve the mean flow features within reasonable accuracy with RANS...

Anna Tian February 5, 2014 05:25

Looking for experimental data for Ahmed body
 
Hi,

I'm looking for Cl and Cd experimental data for Ahmed body. Could anyone kindly provide me that data? I looked for it online but didn't find it. I also asked this question in the main forum. But people tell me that they also don't have Cd or Cl data.


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