Order of numerical scheme

j_h_86 · December 12, 2012, 08:17

Hello,

I did a 2nd order calculation of a laminar flow in CFX which followed a GCI study (refinement factor r=2, 3 grids, asymptotic range (1.001113)). I observed a rate of convergence of p=1.15.
I expected a value a bit less than 2 due to numerical effects but can a value close to 1 still be correct?

Thank you very much in advance!

ghorrocks · December 12, 2012, 16:26

Yes. All the different bits of the equations can converge at different rates - advection could be second order, bit diffusion could be first, etc etc. So if I find I am in the asymptotic range p which is close then I am happy.

December 12, 2012, 08:17	Order of numerical scheme	#1
j_h_86 Member Johannes Ringborn Join Date: Nov 2012 Posts: 40 Rep Power: 13	Hello, I did a 2nd order calculation of a laminar flow in CFX which followed a GCI study (refinement factor r=2, 3 grids, asymptotic range (1.001113)). I observed a rate of convergence of p=1.15. I expected a value a bit less than 2 due to numerical effects but can a value close to 1 still be correct? Thank you very much in advance!

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December 12, 2012, 16:26		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Yes. All the different bits of the equations can converge at different rates - advection could be second order, bit diffusion could be first, etc etc. So if I find I am in the asymptotic range p which is close then I am happy.