Expert-param:: Cht diffusion scheme

PCFD · July 12, 2010, 10:16

Hi,

can anybody tell me what the expert parameter cht diffusion scheme does mean? In which cases does it make sense to set it to its none default-values (=1-4 and 6)?

cht diffusion scheme: Specifies the diffusion scheme for CHT solids: 1=central (interior) , central (boundary); 2=posdef coefficients (interior), central (boundary); 3=posdef values (interior) , posdef values (boundary); 4=blended scheme (interior) , central (boundary); 5=posdef coefficients (interior), posdef values (boundary); 6=blended scheme (interior) , posdef values (boundary)

stumpy · July 12, 2010, 11:14

I can't think of any situation where you'd want to change this. What's the motivation for looking at this?

PCFD · July 12, 2010, 11:23

It would be nice if you let me participate your knowledge about this expert paramerer.

stumpy · July 12, 2010, 14:20

The parameter controls the numerical scheme used to solve the heat diffusion equation in a solid. There's different treatment for boundary nodes and interior nodes. posdef = Positive Definite; you can google this to get more details for the definition of Positive Definite. I assume central means central differencing, but don't know for sure. blended scheme would be a blending, presumably between the central and posdef schemes. "values" refers to the right-hand side of the matrix solution; i.e. if you have [A][x]=[b], then [b] are your "values". "coefficients" refers to [A].

PCFD · July 12, 2010, 14:49

Hi,

thanks for the information.

July 12, 2010, 10:16	Expert-param:: Cht diffusion scheme	#1
PCFD New Member Join Date: May 2009 Posts: 24 Rep Power: 17	Hi, can anybody tell me what the expert parameter cht diffusion scheme does mean? In which cases does it make sense to set it to its none default-values (=1-4 and 6)? cht diffusion scheme: Specifies the diffusion scheme for CHT solids: 1=central (interior) , central (boundary); 2=posdef coefficients (interior), central (boundary); 3=posdef values (interior) , posdef values (boundary); 4=blended scheme (interior) , central (boundary); 5=posdef coefficients (interior), posdef values (boundary); 6=blended scheme (interior) , posdef values (boundary)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Moving mesh	Niklas Wikstrom (Wikstrom)	OpenFOAM Running, Solving & CFD	122	June 15, 2014 07:20
Stress Diffusion Scheme	John S.	CFX	2	September 9, 2008 22:54
asking for a few expert parameter for rotarywing	charles	CFX	4	November 3, 2006 15:15
Time step vs Negative concentration	James	CFX	5	April 19, 2006 19:40
Numerical diffusion error	Z.Zeng	Main CFD Forum	8	October 22, 1999 10:06

July 12, 2010, 11:14		#2
stumpy Senior Member Join Date: Apr 2009 Posts: 531 Rep Power: 21	I can't think of any situation where you'd want to change this. What's the motivation for looking at this?

July 12, 2010, 11:23		#3
PCFD New Member Join Date: May 2009 Posts: 24 Rep Power: 17	It would be nice if you let me participate your knowledge about this expert paramerer.

July 12, 2010, 14:20		#4
stumpy Senior Member Join Date: Apr 2009 Posts: 531 Rep Power: 21	The parameter controls the numerical scheme used to solve the heat diffusion equation in a solid. There's different treatment for boundary nodes and interior nodes. posdef = Positive Definite; you can google this to get more details for the definition of Positive Definite. I assume central means central differencing, but don't know for sure. blended scheme would be a blending, presumably between the central and posdef schemes. "values" refers to the right-hand side of the matrix solution; i.e. if you have [A][x]=[b], then [b] are your "values". "coefficients" refers to [A].

July 12, 2010, 14:49		#5
PCFD New Member Join Date: May 2009 Posts: 24 Rep Power: 17	Hi, thanks for the information.