hi,everybody. My own fem code has caled such a poisson problem succesfully. and now I want to use it as my pressure poisson equations solver. I need a stand veloctiy and pressure distribution at a certain time as my references. Can any bode being successful in the calculation of lid driven flow in a square cavity by using quad element can send me one copy? thank you very much and if you can please help me.

this is the poison example I caled rightly: d2T d2T ---- + ---- = 0 dx2 dy2

For a 2D system reference (x,y) with dimensions W x H you can set for BC:

T = T1 for y = 0 (T1 can be any value, say, 30 oC) T = T1 for x =0 T = T1 for x =W T = Tm sen(pi.x) + T1 for y = H

----

(W)

The exact solution (analitic) for a given node (x,y) is given by

T = Tm senh(pi y/W) sen(pi x/W) + T1

-------------

senh(pi H/W)

oh.sorry, the example expression have strange form here. I write again: d/dx(dt/dx)+d/dy(dt/dy)=0. for a square domain with unit length: t=t1 when x=0,x=1,y=0 t=tm*sin(pi*x)+t1 analytic answer according to JP Holman: t(x,y)=tm*sinh(pi*x)*sin(pi*y)/sinh(pi)+t1 as pi=3.1415926