CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

High Y plus wall values despite sizing, inflation and refinement

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   July 23, 2012, 11:48
Default High Y plus wall values despite sizing, inflation and refinement
  #1
Member
 
nauman hashmi
Join Date: Jun 2012
Posts: 54
Rep Power: 6
nauman55 is on a distinguished road
i am getting high wall y plus values despite sizing, inflation and refinement. i am gtg value in exp of 5 or 4 desired values are for SA model. help required.
regards
nauman55 is offline   Reply With Quote

Old   July 23, 2012, 13:50
Default
  #2
Senior Member
 
flotus1's Avatar
 
Alex
Join Date: Jun 2012
Location: Germany
Posts: 1,311
Rep Power: 22
flotus1 will become famous soon enoughflotus1 will become famous soon enough
Could you rephrase the question? I didn't get it.
flotus1 is offline   Reply With Quote

Old   July 23, 2012, 13:53
Default elaboration of the query
  #3
Member
 
nauman hashmi
Join Date: Jun 2012
Posts: 54
Rep Power: 6
nauman55 is on a distinguished road
sir i am interested to model flow around an aircraft at mach 0.8. i am using SA model and facing problem of high y plus value they are in range of 3 exp 5. i have refined my mesh and changed settings for my inflation layers. however yet the values are not coming down. need guidance on this issue.
regards
nauman55 is offline   Reply With Quote

Old   July 24, 2012, 02:07
Default
  #4
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 19
RodriguezFatz will become famous soon enough
What's the thickness of the first cell at the wing? What's the size of the aircraft?
RodriguezFatz is offline   Reply With Quote

Old   July 24, 2012, 02:19
Default
  #5
Senior Member
 
flotus1's Avatar
 
Alex
Join Date: Jun 2012
Location: Germany
Posts: 1,311
Rep Power: 22
flotus1 will become famous soon enoughflotus1 will become famous soon enough
Did I get you correctly? Althoug you change the thickness of the first cell, the Yplus values do not change?
I can't recall such a bug in Fluent.
flotus1 is offline   Reply With Quote

Old   July 24, 2012, 05:27
Default calrifications
  #6
Member
 
nauman hashmi
Join Date: Jun 2012
Posts: 54
Rep Power: 6
nauman55 is on a distinguished road
the size of aircraft is around 18 m long and the thickness of first layer is 1 exp -7. still the Y plus is very high. may be i am doing some things wrong. the mesh quality as per skewness and orthogonal quality is good.
regards
nauman55 is offline   Reply With Quote

Old   July 24, 2012, 05:30
Default
  #7
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 19
RodriguezFatz will become famous soon enough
So your first layer thickness is 100nm? Did your solution converge? What's the largest residual?
RodriguezFatz is offline   Reply With Quote

Old   July 30, 2012, 14:09
Default Convergence values
  #8
Member
 
nauman hashmi
Join Date: Jun 2012
Posts: 54
Rep Power: 6
nauman55 is on a distinguished road
sir the convergence values are 1 exp -3. i have also used mesh adaptation but no avail. i seek guidance on this regard.
thanx
nauman55 is offline   Reply With Quote

Old   July 31, 2012, 14:20
Default
  #9
Senior Member
 
Join Date: Mar 2011
Location: Germany
Posts: 429
Rep Power: 12
cfd seeker is on a distinguished road
Quote:
Originally Posted by nauman55 View Post
sir the convergence values are 1 exp -3. i have also used mesh adaptation but no avail. i seek guidance on this regard.
thanx
I guess you have not scaled your mesh in fluent, check upon this. BTW you are using structured hexa mesh or tetra mesh for your problem?
cfd seeker is offline   Reply With Quote

Old   July 31, 2012, 14:44
Default RE: CFD seeker sir
  #10
Member
 
nauman hashmi
Join Date: Jun 2012
Posts: 54
Rep Power: 6
nauman55 is on a distinguished road
sir mesh is scaled in the same units. i have tried both hexa and tetra meshes to get desired values but no avail.
regards
nauman55 is offline   Reply With Quote

Old   August 1, 2012, 03:06
Default
  #11
Senior Member
 
Join Date: Mar 2011
Location: Germany
Posts: 429
Rep Power: 12
cfd seeker is on a distinguished road
could you please share your geometry and mesh file with me along with flow and boundary conditions if its not confidential, I will try on it and will let you know.... are you making your mesh in ICEM or Gambit or anyother software?
cfd seeker is offline   Reply With Quote

Old   August 1, 2012, 03:47
Default geometry sharing
  #12
Member
 
nauman hashmi
Join Date: Jun 2012
Posts: 54
Rep Power: 6
nauman55 is on a distinguished road
sure sir if i may have ur email address. my email is naumaneshanhashmi@gmail.com if you can send me a blank email, i will send you the requisite files.
regards
nauman55 is offline   Reply With Quote

Old   August 1, 2012, 10:54
Default
  #13
Senior Member
 
Join Date: Mar 2011
Location: Germany
Posts: 429
Rep Power: 12
cfd seeker is on a distinguished road
Quote:
Originally Posted by nauman55 View Post
sure sir if i may have ur email address. my email is naumaneshanhashmi@gmail.com if you can send me a blank email, i will send you the requisite files.
regards
my email id is yasirforfriends@yahoo.com
cfd seeker is offline   Reply With Quote

Old   August 1, 2012, 15:14
Default
  #14
Senior Member
 
Join Date: Mar 2011
Location: Germany
Posts: 429
Rep Power: 12
cfd seeker is on a distinguished road
kindly mail me the parasolid or acis(sat) version of your geometry as I use ICEM for meshing. Thanks

Regards
cfd seeker is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 22:44.