Unreal vortices in NACA0012 at high angle of attack

parvez2683 · September 17, 2009, 00:03

Hi friends,
I am simulating steady state 2D naca0012 airfoil at high angle of attack. I made the C type grid with 50C*50C dimensions with blunt trailing edge. Everything is good untill when I am trying to simulate it at higher AOA like 16its showing me the vorticity near the two face connections at the trailing edge which seems to be quiet unreal. anybody knows how to fix the problem.
I am attaching the pictures of the airfoil vortices at AOA 16.
http://img32.imageshack.us/img32/3418/62143078.jpg
http://img6.imageshack.us/img6/1402/16041239.jpg
http://img7.imageshack.us/img7/9769/92423939.jpg
http://img6.imageshack.us/img6/3161/15773007.jpg

Case file link:
http://www.4shared.com/file/13324788...rfoil0012.html

tstorm · September 18, 2009, 12:27

It looks like the trouble is grid-generated because both of those regions have high aspect-ratio cells. I've seen similar results in some of my cases. Try adapting the grid in those regions, either in FLUENT or your grid generator. FLUENT would probably be better, so you only adapt the cells in question instead of making the entire grid finer.

September 17, 2009, 00:03	Unreal vortices in NACA0012 at high angle of attack	#1
parvez2683 New Member parvez Join Date: Jun 2009 Posts: 8 Rep Power: 17	Hi friends, I am simulating steady state 2D naca0012 airfoil at high angle of attack. I made the C type grid with 50C*50C dimensions with blunt trailing edge. Everything is good untill when I am trying to simulate it at higher AOA like 16its showing me the vorticity near the two face connections at the trailing edge which seems to be quiet unreal. anybody knows how to fix the problem. I am attaching the pictures of the airfoil vortices at AOA 16. http://img32.imageshack.us/img32/3418/62143078.jpg http://img6.imageshack.us/img6/1402/16041239.jpg http://img7.imageshack.us/img7/9769/92423939.jpg http://img6.imageshack.us/img6/3161/15773007.jpg Case file link: http://www.4shared.com/file/13324788...rfoil0012.html

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September 18, 2009, 12:27		#2
tstorm Member Join Date: Apr 2009 Posts: 78 Rep Power: 18	It looks like the trouble is grid-generated because both of those regions have high aspect-ratio cells. I've seen similar results in some of my cases. Try adapting the grid in those regions, either in FLUENT or your grid generator. FLUENT would probably be better, so you only adapt the cells in question instead of making the entire grid finer.