boundary layer grid resolution for Spalart-Allmaras model

wei_wu · June 21, 2009, 16:28

hello everyone!

I have some questions about the boundary layer cells thickness for the S-A model.

1.. I understand that in order to get better results by using S-A model without wall function you need to make yPlus in the range of order 1. I wonder how the results will be if I use a much finer bundary layer grids , like yPlus in the order of 0.001? Is it just a waste of time without any improvement of the results or it will yield a worse one.

2.. how many cells in the boundary layer in the direction normal to the wall is a good choice, any guidelines?

3..if I use the boundary layer cells which have high aspect ratio like over 100, will that affect the accuracy a lot?

Thank you all for reading.

Wei

wei_wu · June 23, 2009, 16:53

anyone has any ideas? thanks

June 21, 2009, 16:28	boundary layer grid resolution for Spalart-Allmaras model	#1
wei_wu New Member wei wu Join Date: Mar 2009 Location: us Posts: 14 Rep Power: 17	hello everyone! I have some questions about the boundary layer cells thickness for the S-A model. 1.. I understand that in order to get better results by using S-A model without wall function you need to make yPlus in the range of order 1. I wonder how the results will be if I use a much finer bundary layer grids , like yPlus in the order of 0.001? Is it just a waste of time without any improvement of the results or it will yield a worse one. 2.. how many cells in the boundary layer in the direction normal to the wall is a good choice, any guidelines? 3..if I use the boundary layer cells which have high aspect ratio like over 100, will that affect the accuracy a lot? Thank you all for reading. Wei

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June 23, 2009, 16:53		#2
wei_wu New Member wei wu Join Date: Mar 2009 Location: us Posts: 14 Rep Power: 17	anyone has any ideas? thanks