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 keitee July 15, 2002 09:33

BC at airfoil TE

Hi everyone. I wish to know how best to set a TE boundary condition for 2D airfoil calculation, when TE has some thickness. Governing EQ is 2D Navier-Stokes. and geometry is C type. Anyone can help me?

 Li Yang July 15, 2002 09:48

Re: BC at airfoil TE

Hi,

It will be good to insert another block behind the TE.

Regards

Li

 kenn July 15, 2002 11:31

Re: BC at airfoil TE

what does TE represent?

 Peter Attar July 15, 2002 13:13

Re: BC at airfoil TE

Trailing Edge

 Axel Rohde July 15, 2002 13:42

Re: BC at airfoil TE

If you have a C-grid, you really want a sharp trailing edge, otherwise you are better off with an O-grid. So I would say the quickest way will be to fix your TE, i.e. make the two points defining the blunt edge coincide, which makes it sharp.

 Li Yang July 15, 2002 16:39

Re: BC at airfoil TE

I think you are right. It will be the quickest way by using O-grid. Enough grid points can be employed at the trailing edge so that the wake can be captured. However, for this case with a structured grid topology, good quality grid can only be achieved by using multiblock.

Regards

Li

 Axel Rohde July 15, 2002 17:28

Re: BC at airfoil TE

I am not sure about the thickness of this TE, but if it's less than 1% of chord, I would not even bother modeling it. Drag prediction for airfoils, even with a full Navier Stokes solver and the 'right' turbulence model, is a shot in the dark, whereas the TE thickness effect on lift is negligible.

If he uses an O-grid, he will have to throw a lot of points on this TE to make it numerically round. Otherwise he will have non-smooth transformation metrics at the 'kink', which will most likely create numerical problems for the solver. My recommendation: stay with the C-grid and make the edge sharp. For a C-grid, a sharp TE does not pose any problem (metrics are perfectly smooth).

 xxx July 23, 2002 10:54

Re: BC at airfoil TE

Refer to Jack Moran Computational Fluid Dynamics

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