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-   -   Shape function of P1isoP2/P2 triangle element (http://www.cfd-online.com/Forums/main/2669-shape-function-p1isop2-p2-triangle-element.html)

Fengchan Cao October 7, 2000 00:19

Shape function of P1isoP2/P2 triangle element
 
Dear All.

Could you recomend me a source (book or article) with detail of the shape function of P1isoP2/P2 triangle element that used in N3S software.

Thanks

Fengchan Cao October 7, 2000 00:23

Re: Shape function of P1isoP2/P1 triangle element
 
Dear All,

Sorry, that should be P1isoP2/P1 triangle element

Thanks

Sebastien Perron October 8, 2000 14:27

Re: Shape function of P1isoP2/P1 triangle element
 
The report on N3S code is a good reference:

Chabard J.P., Projet N3S de mecanique des fluides, manuel theorique - version 2.0. HE-41/88.09. 1989 EDF.

But these shape functions can be described very easily (from Burnett):

On each triangle, The shape functions for P1 approximation are the following:

uj(x,y)=(aj+bj*x+cj*y)/2Delta, j=1,2,3

aj=xk*yl-xl*yk bj=yk-yl cj=xl-xk delta=area on triangle

and the subscripts j,k,l have the values 1,2,3 for u1 and are permuted cyclically for u2 and u3.

Here, u can be any functions (velocity, pressure).

For P1isoP2/P1, the pressure is interpolated on the big triangles. These triangles are splitted into four triangles and the velocity is interpolated on each of these triangles.


Fengchan Cao October 8, 2000 20:25

Re: Shape function of P1isoP2/P1 triangle element
 
I see. Thank you very much!


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