# Convergence second order

 Register Blogs Members List Search Today's Posts Mark Forums Read

 October 15, 2007, 04:13 Convergence second order #1 KS Guest   Posts: n/a Hi, why when increase the proportional number of cells in my mesh the problem does not converge in second order? thanks

 October 15, 2007, 08:41 Re: Convergence second order #2 Woo Meng Wai Guest   Posts: n/a Hard to say why this happens. Have you tried interating in 1st order first and then switching to second order? But what is important to take note is that having higher number of cells does not mean giving better results. From some of the simulations that we are doing, having too many cells might actually result in unrealistic simulations. Might be good to do a mesh independence test to determine which range of 'cell number' is suitable for your case.

 October 15, 2007, 08:51 Re: Convergence second order #3 KS Guest   Posts: n/a hi, thanks so much! Yes, I started with first order and later I passed to second order but he did not converge how I make this mesh independence test?

 October 15, 2007, 20:02 Re: Convergence second order #4 Woo Meng Wai Guest   Posts: n/a To test for mesh independence: One way is to just start off with an appropriate mesh size that you think is appropriate. Get a converged solution. Plot a certain parameters for comparison which is relevant to your case. [Eg. In my case for a cylinder-on-cone spray dryer, I plot the axial velocity at a certain elevation for the whole cross section.] Now reduce / increase the mesh size and repeat the procedure. Compare the plots of the parameters and see if there are any changes. If the changes is minimal, ~5%, then it is mesh independent. P.S. Not sure on the convergence of your case. You can try adjusting the underrelaxation factors.

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post colopolo CFX 13 October 4, 2011 22:03 RameshK Main CFD Forum 7 July 17, 2010 14:13 jack1980 FLUENT 0 March 28, 2010 11:59 antonio FLUENT 4 December 16, 2004 09:37 Erich FLUENT 0 August 12, 2004 12:05

All times are GMT -4. The time now is 11:23.