# Expert-param:: Cht diffusion scheme

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 July 12, 2010, 09:16 Expert-param:: Cht diffusion scheme #1 New Member   Join Date: May 2009 Posts: 24 Rep Power: 14 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)

 July 12, 2010, 10:14 #2 Senior Member   Join Date: Apr 2009 Posts: 531 Rep Power: 18 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, 10:23 #3 New Member   Join Date: May 2009 Posts: 24 Rep Power: 14 It would be nice if you let me participate your knowledge about this expert paramerer.

 July 12, 2010, 13:20 #4 Senior Member   Join Date: Apr 2009 Posts: 531 Rep Power: 18 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, 13:49 #5 New Member   Join Date: May 2009 Posts: 24 Rep Power: 14 Hi, thanks for the information.