NACA0012 - High Resolution - No convergence

bonestruca · March 25, 2011, 07:35

Hi,
I can't get my solution to convergence when using the High Resolution solver and medium to fine grids. It only convergences on a very coarse grid. Using the Upwind scheme which lacks accuracy - the solution converges every time !
Mach number is 0.5 and angle of attack 2°. With High Resolution I even get negative pressure forces on the wing in x-direction, totally absurd.
What might be the reasons for this behavior and how do I get it to converge ?
Thank you !

siw · March 25, 2011, 16:39

Could you try running a high resolution scheme simulation with the results from the upwind scheme to initialise the solution?

bonestruca · March 25, 2011, 17:09

I tried that and failed.
However I managed to get it to work, I found out that while increasing the number of grid points in the far field and number of inflation layers I did not increase the number of grid points on my airfoil in the same manner. This resulted in long and very thin inflation layer cells, which seem to cause problems with the High Resolution Solver. So I added more points to my profile, decreased the amount of inflation layers and now everything works very well !

March 25, 2011, 07:35	NACA0012 - High Resolution - No convergence	#1
bonestruca New Member Join Date: Jun 2010 Posts: 4 Rep Power: 16	Hi, I can't get my solution to convergence when using the High Resolution solver and medium to fine grids. It only convergences on a very coarse grid. Using the Upwind scheme which lacks accuracy - the solution converges every time ! Mach number is 0.5 and angle of attack 2°. With High Resolution I even get negative pressure forces on the wing in x-direction, totally absurd. What might be the reasons for this behavior and how do I get it to converge ? Thank you !

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
how to understand high resolution scheme and high order scheme	iilw1314	Main CFD Forum	7	April 12, 2022 13:29
high resolution scheme	az_f	CFX	0	November 24, 2010 23:52
larger blend factor or high resolution ?	amine	CFX	2	March 4, 2008 21:28
upwind vs high resolution	Richard	CFX	3	February 20, 2006 07:35
Multicomponent fluid	Andrea	CFX	2	October 11, 2004 06:12

March 25, 2011, 16:39		#2
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 739 Rep Power: 26	Could you try running a high resolution scheme simulation with the results from the upwind scheme to initialise the solution?

March 25, 2011, 17:09		#3
bonestruca New Member Join Date: Jun 2010 Posts: 4 Rep Power: 16	I tried that and failed. However I managed to get it to work, I found out that while increasing the number of grid points in the far field and number of inflation layers I did not increase the number of grid points on my airfoil in the same manner. This resulted in long and very thin inflation layer cells, which seem to cause problems with the High Resolution Solver. So I added more points to my profile, decreased the amount of inflation layers and now everything works very well !