CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum

Airfoil grid for turbulent flows: high aspect ratios

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

LinkBack Thread Tools Display Modes
Old   September 29, 2012, 04:45
Default Airfoil grid for turbulent flows: high aspect ratios
New Member
Marco Caboni
Join Date: Sep 2012
Posts: 1
Rep Power: 0
Marconi is on a distinguished road
Dear all,

Lately I developed a structured C-Grid around an airfoil which uses about 103,000 points in the whole computational domain. Specifically, it has got 440 points around the airfoil and 100 points in its wake. The farfield was set at 50 airfoil cords (the chord is equal to 1 m).

This grid was generated for a Re number equal to 1e6 and a y+ equal to 0.5 (the solver uses the sst turbulence model). Therefore, this grid has a minimum grid-wall distance equal to 1e-5 m.

This very small minimum grid-wall distance leads to very high aspect ratios around the airfoil (the max AR around the airfoil is about 1000), and even higher ARs in its wake (200,000).

If the Re number increases these ARs will increase proportionally. For a Re number of 10e6 the maximum AR around the airfoil can reach 10.000.

My question is: in your experience might these ARs affect my simulation results? Is there a way (using structured grids) to decrease these ARs without increasing the number of points?

Many thanks for your help.

Regards to all,

Marconi is offline   Reply With Quote

Old   September 29, 2012, 13:01
Senior Member
Martin Hegedus
Join Date: Feb 2011
Posts: 467
Rep Power: 9
Martin Hegedus is on a distinguished road
The grid you have sounds about standard. For a 2D grid some people like to go out a little further than 50 chords. Maybe 100 to 150. But, that doesn't make too much difference. Try it for a moderate angle of attack. As for the AR, it is what it is. You're biggest error will come from the turbulence modeling at higher angles of attack, i.e. stall.
Martin Hegedus is offline   Reply With Quote


airfoil, aspect ratio, structured grid, turbulence analysis

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Grid generation of an airfoil in Ansys workbench 12.1 sunish5 ANSYS 1 October 26, 2010 23:29
Do high grid resolution capture accurate shocks? Explicit someone Main CFD Forum 1 November 10, 2008 06:48
mesh for a high aspect ratio geometry matthias CFX 3 October 20, 2006 02:55
2D Simulation Airfoil Aspect Ratio Kramer CFX 7 February 6, 2006 14:35
Aspect Ratio at high turbulent and swirled flows zago FLUENT 0 May 19, 2004 02:37

All times are GMT -4. The time now is 03:15.