Helmholtz solver excitation at selected node

[iczajka]

Hi everybody,
I'm currently working on a few acoustical analysis examples.
So I am trying to set pressure at selected node (something like point sound source), is there a elegant way to do it?
Or have I do some fortran-ing?

Irek

[raback]

Hi

Create a new BC section and instead of refering to "Target Boundaries" give "Target Coordinates". The closest node to the coordinate value will be chosen, for example

Code: Select all

Boundary Condition 7
  Name = "FixedNode"
  Target Coordinates(1,3) = 1.2 2.3 0.0
  Pressure 1 = Real 0.0
End 

The info of this and "Target Nodes" shoud be available also in ElmerSolver Manual. Look from the Index.

-Peter

[iczajka]

Thank you for quick response. And please forgive me for my laziness

I'm reading manual.

Irek

[iczajka]

Hello again
I am trying this boundary condition, but ElmerSolver says

SolveSystem: Solution trivially zero!

I don't understand why?

BR
Irek

[mzenker]

Hi,

it seems to me that ElmerSolver has not understood your boundary condition, maybe due to a trivial error in the sif file. This may happen e.g. if you have loaded a new mesh into an existing project. You have then to re-allocate the boundaries to their respective boundary conditions.
I would read the sif file thoroughly and check that everything is declared as it should.

HTH,

Matthias

[iczajka]

Ok, there is my .sif file.
To be specific: I want to declare pressure at given point _inside_ not at the boundary of solution area.

BR
Irek

[mzenker]

Hi,

I cannot see what is wrong with your sif file. Only one solver seems to be used, but all the BC's seem to be there. Maybe someone else can see more than I do?

Sorry,

Matthias

[raback]

Hi, When your field is named "Pressure Wave" the Dirichlet condition should be given to "Pressure Wave 1" and "Pressure Wave 2", correspondingly. -Peter

[iczajka]

Thank You,
that was mistake - my mistake, I just mindless copied example from forum.

BR
Irek