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

Re: Shape function of P1isoP2/P1 triangle element
 

Dear All,

Sorry, that should be P1isoP2/P1 triangle element

Thanks

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.

Re: Shape function of P1isoP2/P1 triangle element
 

I see. Thank you very much!