what is the actual order in a shock region

mym1411 · March 17, 2010, 07:14

Hi
I have a quick question, please
I use a second order accurate scheme to solve a problem involving a shock wave (density-based solver). I was told hat in the regions of high gradients (as in the case of shock wave), Fluent switches to a first order scheme, so the final accuarcy will be a first order anyway . Is that true?

Thanks

DoHander · March 17, 2010, 10:57

Usually a high order scheme (like the one used in Fluent) uses the so called limtator functions near a shock wave - which will actually switch to a first order scheme near a shock wave.

Read any basic CFD book and you will understand exactly why we need to use limiters in these regions.

Do

muketa · March 18, 2010, 04:53

DoHander
is there a reference in Fluent documentation for what you have just said? I've tried to search, but i can't find it...

Also i would appreciate if you could suggest some good references that deal with shock wave simulation in CFD...

Thanks,
muketa

DoHander · March 18, 2010, 08:01

For theory - try "Modern compressible flow" by J.D.Anderson
For CFD - "Numerical simulation of internal and external flows" by Hirsch (especially volume II).

Here is a better explanation (not written by me) of what I mean:

http://www.cfd-online.com/Wiki/Flux_limiters

Do

March 17, 2010, 07:14	what is the actual order in a shock region	#1
mym1411 New Member mahmoud Join Date: Mar 2010 Posts: 3 Rep Power: 16	Hi I have a quick question, please I use a second order accurate scheme to solve a problem involving a shock wave (density-based solver). I was told hat in the regions of high gradients (as in the case of shock wave), Fluent switches to a first order scheme, so the final accuarcy will be a first order anyway . Is that true? Thanks

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March 17, 2010, 10:57		#2
DoHander Senior Member Join Date: Nov 2009 Posts: 411 Rep Power: 19	Usually a high order scheme (like the one used in Fluent) uses the so called limtator functions near a shock wave - which will actually switch to a first order scheme near a shock wave. Read any basic CFD book and you will understand exactly why we need to use limiters in these regions. Do

March 18, 2010, 04:53		#3
muketa New Member Join Date: Jul 2009 Posts: 7 Rep Power: 16	DoHander is there a reference in Fluent documentation for what you have just said? I've tried to search, but i can't find it... Also i would appreciate if you could suggest some good references that deal with shock wave simulation in CFD... Thanks, muketa

March 18, 2010, 08:01		#4
DoHander Senior Member Join Date: Nov 2009 Posts: 411 Rep Power: 19	For theory - try "Modern compressible flow" by J.D.Anderson For CFD - "Numerical simulation of internal and external flows" by Hirsch (especially volume II). Here is a better explanation (not written by me) of what I mean: http://www.cfd-online.com/Wiki/Flux_limiters Do