[Getdp] result all zero
Christophe Geuzaine
Christophe.Geuzaine at ulg.ac.be
Tue Oct 30 09:36:35 CET 2001
Lin Ji wrote:
>
> Hi, Christophe,
> I am not trying to solve the original wave equation in frequency domain.
> I am solving the Helmholtz equation
> u_xx + u_yy + (\tau^2 / c^2)u = 0
> directly where the subscript _xx denotes the 2nd partial derivative to x and
> \tau corresponds to a specific frequency. I had the following formulation for
> the above equation:
>
> Formulation {
> { Name hhltz; Type FemEquation;
> Quantity {
> { Name u; Type Local; NameOfSpace Hgrad; }
> }
> Equation {
> Galerkin { [ tau_c*tau_c/mu[] * Dof{u} , {u} ];
> In Omega; Integration I1; Jacobian JVol; }
>
> Galerkin { [ -Dof{d u} , {d u} ];
> In Omega; Integration I1; Jacobian JVol; }
>
> Galerkin { [ f_bc[] , {u} ];
> In Gamma_f; Integration I1; Jacobian JSur; }
> }
> }
> }
>
> where mu[] = c^2 and tau_c denotes the central frequency and f_bc[] is the
> Neumann boundary condition. They are all defined in the Function object.
Ok. I tried your formulation on a simple rectangular mesh, and I get a
solution... Maybe your mesh is wrong?
--
Christophe Geuzaine
Tel: 32 (0) 4 366 37 10 http://geuz.org
Fax: 32 (0) 4 366 29 10 mailto:Christophe.Geuzaine at ulg.ac.be