dolfin team mailing list archive

[Alexander Jarosch <alexanj@xxxxx>]

I use a direct solver and I have a boundary where the velocities = 0 and 
on that boundary the pressure fluctuates even with a mixed Taylor-Hood 
approch.

Alex

Garth N. Wells wrote:

> On Tue, 2006-05-23 at 14:46 +0000, Alexander Jarosch wrote:
>  
>
> > Hi,
> >
> > did anyone play around with the stokes solver on more complex 
> > geometries? 
> >    
>
> The demo in src/demo/pde/convection-diffusion solves the Stokes problem
> around a dolphin using a Taylor-Hood element and the result looks OK.
>
> Garth
>
>
>  
>
> > I only seem to get something senseful using a stabalized 
> > stokes like:
> >
> > scalar = FiniteElement("Lagrange", "triangle", 1)
> > vector = FiniteElement("Vector Lagrange", "triangle", 2)
> > system = vector + scalar
> >
> > (v, q) = TestFunctions(system)
> > (u, p) = TrialFunctions(system)
> >
> > f = Function(vector)
> > h = Function(scalar)
> > nu = Function(scalar)
> >
> > beta  = 0.2
> > delta = beta*h*h
> >
> > a = (nu*dot(grad(v), grad(u)) - div(v)*p + q*div(u) + delta*dot(grad(q), 
> > grad(p)))*dx
> > L = dot(v + mult(delta, grad(q)), f)*dx
> >
> > which is fine, but when I compare the solution to another FEM package, 
> > they do not quite match. Was there already some benchmarking done?
> >
> > cheers,
> >
> > Alex
> >    
>
>
>
> _______________________________________________
> DOLFIN-dev mailing list
> DOLFIN-dev@xxxxxxxxxx
> http://www.fenics.org/cgi-bin/mailman/listinfo/dolfin-dev
>
>  


--
Alexander H. Jarosch

Jarðvísindastofnun Háskólans
Institute of Earth Sciences, University of Iceland
Náttúrufræðahús, Askja
Building of Natural Sciences, Askja
Sturlugata 7
IS - 101 Reykjavík
Iceland

Tel.: +354 525 4906
http://raunvis.hi.is/~jarosch/