Upwind scheme

September 25, 2007, 19:45

Hi there,

I know that upwind scheme should only be used for the initial guess but not for the final results. Can we believe on results from upwind upto an extent, to do some analysis if our model physics is working fine ? Or these results are not good for any kind of analysis ?

Regards, KM.

September 26, 2007, 00:21

Hi,

Problem dependant, so cannot give a general answer. Do a run using both and compare for your application.

Glenn Horrocks

dgfemkadri · September 26, 2007, 12:10

Hi KM,

All CFD analysis includes some degree of error. Running with a first order upwind advection scheme simply means that the error is going to be larger for a given grid resolution and therefore will require a much finer mesh to minimize this error.

An easy way to estimate the magnitude of this error is to compare results using upwind to High Resolution or a Specified Blend Factor. You'll find that the difference is largest on a coarse mesh and is reduced as you refine the mesh.

-CycLone

September 27, 2007, 15:41

Thanks a ton ! It helps.

Regards, Kushagra.

September 27, 2007, 15:41

Thanks a ton ! It helps.

Regards, Kushagra.

September 25, 2007, 19:45	Upwind scheme	#1
KM Guest Posts: n/a	Hi there, I know that upwind scheme should only be used for the initial guess but not for the final results. Can we believe on results from upwind upto an extent, to do some analysis if our model physics is working fine ? Or these results are not good for any kind of analysis ? Regards, KM.

September 26, 2007, 00:21	Re: Upwind scheme	#2
Glenn Horrocks Guest Posts: n/a	Hi, Problem dependant, so cannot give a general answer. Do a run using both and compare for your application. Glenn Horrocks

September 26, 2007, 12:10	Re: Upwind scheme	#3
CycLone Guest Posts: n/a	Hi KM, All CFD analysis includes some degree of error. Running with a first order upwind advection scheme simply means that the error is going to be larger for a given grid resolution and therefore will require a much finer mesh to minimize this error. An easy way to estimate the magnitude of this error is to compare results using upwind to High Resolution or a Specified Blend Factor. You'll find that the difference is largest on a coarse mesh and is reduced as you refine the mesh. -CycLone dgfemkadri likes this.

September 27, 2007, 15:41	Re: Upwind scheme	#4
Kushagra Mittal Guest Posts: n/a	Thanks a ton ! It helps. Regards, Kushagra.

September 27, 2007, 15:41	Thanks: Upwind scheme	#5
Kushagra Mittal Guest Posts: n/a	Thanks a ton ! It helps. Regards, Kushagra.

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