CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > ANSYS Meshing & Geometry

[GAMBIT] Asking Y plus

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 14, 2009, 07:10
Question Asking Y plus
  #1
Senior Member
 
teguhtf's Avatar
 
teguh hady
Join Date: Aug 2009
Location: Surabaya, Indonesia
Posts: 153
Rep Power: 7
teguhtf is on a distinguished road
Dear All,
In simulating airfoil, i use y+ = 1 for thin layer. However, I don't know the correct value of grow ratio b/a and number of row in GAMBIT??
Help me out this problem!!!
Thanks
teguhtf
__________________
Now Or Never!!!
teguhtf is offline   Reply With Quote

Old   November 15, 2009, 17:16
Default Problem Dependent.
  #2
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,662
Blog Entries: 1
Rep Power: 35
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
These are up to the user and are highly problem dependent. If you don't already have a preference, then you should start with a ratio of 1.2 (most common).

As for number of layers, this should be enough to capture the thickness of your boundary layer velocity profile, but not so thick that it causes you too much meshing trouble.

Try 5, or try 21, solve, and look at the boundary layer velocity profiles... Which works best for your type of model? You want to see a smoothly transitioning boundary layer profile that goes from 0 at the wall up to the free-stream velocity (should approach asymptoticly )before the top of the prism stack.

Was 21 layers overkill or does it look like you need more?
PSYMN is offline   Reply With Quote

Old   November 21, 2009, 21:11
Default
  #3
Senior Member
 
teguhtf's Avatar
 
teguh hady
Join Date: Aug 2009
Location: Surabaya, Indonesia
Posts: 153
Rep Power: 7
teguhtf is on a distinguished road
Thank you for your reply,
Well, My problem is How to get Right value of Cd & Cl between experiment and
simulation. Can you explain the Y+ value of other boundary condition?? Do you have reference?? Btw, I've try
5 to 10 layers. But it doesn't work!! My simulation is just 2D so i can use prism.
Thanks for helping
Teguh
__________________
Now Or Never!!!
teguhtf 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 02:08.