CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent UDF and Scheme Programming

DEFINE_CG_MOTION and DEFINE_GRID_MOTION for same zone type (boundary)

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

LinkBack Thread Tools Search this Thread Display Modes
Old   April 26, 2022, 18:37
Post DEFINE_CG_MOTION and DEFINE_GRID_MOTION for same zone type (boundary)
New Member
Nick 0704
Join Date: Oct 2021
Posts: 2
Rep Power: 0
NickZonzini is on a distinguished road
Hi to everybody,

I'm tackling a 2D transient problem of an airfoil that is supposed to oscillate and simultaneously deflect it leading edge. The domain layout is depicted in the attached figure.

Basically, what I'm aiming to obtain is an airfoil that harmonically oscillate around it's axis at 0.25 chord lenght, and that at a given time step start also to deform accordignly to specific equations the leading edge.

For the first simulation of pure pitching motion of the airfoil I created a UDF with the DEFINE_CG_MOTION macro. In the dynamic mesh zone I decleared as rigid body both airfoil boundary (boundary condition) and inner rotating grid (Cell Zone Condition), and as deforming the rest of the doamin. The obtained results showed a good agrement with other published results, ok so far.
For the leadinge edge deformation I created a UDF with DEFINE_GRID_MOTION macro to modify the interested portion of the airfoil. Here, I set up as User-Defined the airfoil boundary (boundary condition) and as deforming the inner rotating grid (Cell Zone Condition). Also for this single motion everthing was working perfectly.

How can I specify CG_MOTION and GRID_MOTION at the same time to the airfoil boundary ? one possible logical solution would be that the first function (CG MOTION) rotate each node of the airfoil boundary along with the internal domain, and only afterward the second function of the UDF (GRID MOTION) move the nodes of the leading edge. Simultaneously also the internal domain should behave first as a rigid body and then (when the airfoil deformation apply) as a deforming for allow the adjacent mesh to adapt to the new modified airfoil boundary. How can I achieve that?
Should I implement this algorithm inside a UDF?

Any suggestion/tip or solutions for this problem is highly appriciated.

Many Thanks to all of you
Attached Images
File Type: png domain.png (43.2 KB, 5 views)

Last edited by NickZonzini; April 27, 2022 at 06:15.
NickZonzini is offline   Reply With Quote


define_cg_motion, define_grid_motion, define_zone_motion, dynamic mesh zones, udf

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Multiphase euler foam problem with velocity vector enthusiast OpenFOAM Running, Solving & CFD 1 January 20, 2023 03:54
Error - Solar absorber - Solar Thermal Radiation MichaelK CFX 12 September 1, 2016 05:15
Divergent temperature in chtMultiRegion(Simple)Foam akrasemann OpenFOAM Running, Solving & CFD 13 March 24, 2014 02:54
[swak4Foam] Air Conditioned room groovyBC Sebaj OpenFOAM Community Contributions 7 October 31, 2012 14:16
Pressure instability with rhoSimpleFoam daniel_mills OpenFOAM Running, Solving & CFD 44 February 17, 2011 17:08

All times are GMT -4. The time now is 21:28.