Search found 79 matches

by CrocoDuck
05 Jun 2021, 16:08
Forum: ElmerSolver
Topic: Confusing results open-closed duct acoustics harmonic analysis simulation
Replies: 8
Views: 845

Re: Confusing results open-closed duct acoustics harmonic analysis simulation

Hi I had time to have a look at this thread. Some comments 1) The natural BCs (do nothing) should be fine for symmetry. Even for double symmetry. 2) The asymmetry of the mesh may break the symmetry a little if the solution is sensitive to mesh quality. This may be particularly true for resonance. 3...
by CrocoDuck
29 May 2021, 15:46
Forum: ElmerSolver
Topic: Confusing results open-closed duct acoustics harmonic analysis simulation
Replies: 8
Views: 845

Re: Confusing results open-closed duct acoustics harmonic analysis simulation

Hi there! I took at look at your study. I think there are a couple of issues. Plane Wave Outlet: Boundary Condition 3 Target Boundaries(1) = 3 Name = "nrbc" Wave impedance 1 = Real MATC "343*p" Wave impedance 2 = 0 End This is wrong. If you look at the Elmer Models Manual you wil...
by CrocoDuck
28 May 2021, 21:27
Forum: ElmerSolver
Topic: Confusing results open-closed duct acoustics harmonic analysis simulation
Replies: 8
Views: 845

Re: Confusing results open-closed duct acoustics harmonic analysis simulation

Hi again, Sorry, I completely misunderstood your problem somehow, despite there being a very clear diagram. You are right, at the open end you should not use the plane wave outlet condition, but not the piston one either. There are perhaps formulas for the radiation impedance of an anular radiator, ...
by CrocoDuck
28 May 2021, 17:58
Forum: ElmerSolver
Topic: Confusing results open-closed duct acoustics harmonic analysis simulation
Replies: 8
Views: 845

Re: Confusing results open-closed duct acoustics harmonic analysis simulation

Hi there! I am glad my tutorial was helpful for you! I cannot quite comment on the issue about the iterations, but I have a comment about this: Because a considerable portion of the opening is blocked by the radiator and I would like to study the frequency spectrum up to wave lengths of only 1 to 2 ...
by CrocoDuck
20 May 2021, 12:02
Forum: ElmerSolver
Topic: HelmholtzSolve Outputs a Vector Result for 2D Mesh Study
Replies: 5
Views: 686

Re: HelmholtzSolve Outputs a Vector Result for 2D Mesh Study

Hi, thank you very much. I tried it and I got a vector field result again: Simulation Max Output Level = 5 Coordinate System = "Cartesian 2D" Coordinate Mapping(3) = 1 2 3 Simulation Type = Steady state Steady State Max Iterations = 1 Output Intervals = 1 Coordinate Scaling = 0.001 Solver ...
by CrocoDuck
19 May 2021, 11:55
Forum: ElmerSolver
Topic: HelmholtzSolve Outputs a Vector Result for 2D Mesh Study
Replies: 5
Views: 686

Re: HelmholtzSolve Outputs a Vector Result for 2D Mesh Study

I think I figured out what makes the "pressure wave" vector field to happen. I am preparing my mesh with Salome. If the root geometric entity that I mesh is a "Face" then the results will have a "pressure wave" vector field. Does any of you guys know what would be the b...
by CrocoDuck
14 May 2021, 18:57
Forum: ElmerSolver
Topic: HelmholtzSolve Outputs a Vector Result for 2D Mesh Study
Replies: 5
Views: 686

Re: HelmholtzSolve Outputs a Vector Result for 2D Mesh Study

That's intriguing... I setup two very similar studies and I ended up with "pressure wave 1" and "pressure wave 2"... Maybe I did something weird by mistake with the first one...
by CrocoDuck
14 May 2021, 16:51
Forum: ElmerSolver
Topic: HelmholtzSolve Outputs a Vector Result for 2D Mesh Study
Replies: 5
Views: 686

HelmholtzSolve Outputs a Vector Result for 2D Mesh Study

Hi! I used the Helmholtz Solver for acoustics a bunch of times for 3D meshes. Typically, the vtu file Elmer saves has two scalar fields inside, "pressure wave 1" and "pressure wave 2". Today I produced a simulation on a 2D mesh instead, on the XY plane. After I solved the study, ...
by CrocoDuck
12 May 2021, 18:17
Forum: ElmerSolver
Topic: Setting up a HelmholtzBEM Study
Replies: 2
Views: 587

Re: Setting up a HelmholtzBEM Study

Makes sense, thanks for the insight!
by CrocoDuck
12 May 2021, 14:55
Forum: ElmerSolver
Topic: Setting up a HelmholtzBEM Study
Replies: 2
Views: 587

Setting up a HelmholtzBEM Study

Hi, I would like to setup a study with the HelmholtzBEM solver. The problem would look similar to the AcouSTO Engines' shielding effect tutorial (page 20): I have a source in the middle of a domain and I am interested in the pressure on a sphere around it. For example, I might have a 2D disk (but I ...