unable to simulate an airplane wing

hedley · May 18, 2014, 03:54

I have lost the plot - run su2 on airplane wing which has 1.6meter chord - 800mm tip and 3 meter half span . Set .cfg file for +- 75 KTS and have tried many diff parameters and solution methods . The outputs just don't make sense . Attached find CL and CD for a 7 degree AOA ????

any assistance in where I have gone wrong . i have attached .cfg settings

fpalacios · May 18, 2014, 22:19

Quote:

Originally Posted by hedley

I have lost the plot - run su2 on airplane wing which has 1.6meter chord - 800mm tip and 3 meter half span . Set .cfg file for +- 75 KTS and have tried many diff parameters and solution methods . The outputs just don't make sense . Attached find CL and CD for a 7 degree AOA ????

any assistance in where I have gone wrong . i have attached .cfg settings

I think it could be related with the non-dimensionalization... there is something strange... SU2 says that the z projection is ~6000m2? Could you please double check that the grid is in meters? On the other hand, it would be great if you run the code dimensionally

% Reference pressure (1.0 N/m^2 by default, only for compressible flows)
REF_PRESSURE= 1.0
%
% Reference temperature (1.0 K by default, only for compressible flows)
REF_TEMPERATURE= 1.0
%
% Reference density (1.0 Kg/m^3 by default, only for compressible flows)
REF_DENSITY= 1.0

Best,
Francisco

hedley · May 19, 2014, 15:58

The grid was done in pointwise in inches so I have scaled to meters and also as suggested set all values to 1 to get a dimensioned result. The solver still has Cl and cd increasing on each iteration ? . Using AVL from Drela I get some idea of what I should expect but SU2 seems to be way out on these . I'm sure it is a setting or .... Many

demanosalvas · June 5, 2014, 16:29

Hedley,

Is your simulation converged? If you are running RANS, are you using a mesh with the right y+ and at least 20 elements in the boundary layer? Some times when running viscous problems you need to tweak some of the parameters such as the CFL number to improve your convergence rate, but in any case you will need to run this simulation for a few thousand iterations before you can see any meaningful results.

Hope this helps,

David

May 19, 2014, 15:58	Wing analysis problems	#3
hedley Member Hedley Join Date: May 2014 Posts: 52 Rep Power: 12	The grid was done in pointwise in inches so I have scaled to meters and also as suggested set all values to 1 to get a dimensioned result. The solver still has Cl and cd increasing on each iteration ? . Using AVL from Drela I get some idea of what I should expect but SU2 seems to be way out on these . I'm sure it is a setting or .... Many

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[ICEM] Blocking For Swept Wing	air_engineer_arsenal	ANSYS Meshing & Geometry	13	July 24, 2012 12:52
[ICEM] Meshing of a closed wing	Lukas_ZH	ANSYS Meshing & Geometry	34	July 6, 2012 08:15
[snappyHexMesh] Meshing 3D wing (hydrofoil) fails	klausb	OpenFOAM Meshing & Mesh Conversion	0	December 28, 2011 15:26
Lift and Drag on airplane wing	Arj	CFX	4	October 6, 2006 05:05
Ansys/Flotran 3D Wing Analysis	George	Main CFD Forum	0	January 29, 2002 10:44

June 5, 2014, 16:29		#4
demanosalvas New Member David Manosalvas-Kjono Join Date: Feb 2014 Posts: 25 Rep Power: 12	Hedley, Is your simulation converged? If you are running RANS, are you using a mesh with the right y+ and at least 20 elements in the boundary layer? Some times when running viscous problems you need to tweak some of the parameters such as the CFL number to improve your convergence rate, but in any case you will need to run this simulation for a few thousand iterations before you can see any meaningful results. Hope this helps, David