Search found 108 matches

by Gary R
12 Apr 2021, 03:43
Forum: ElmerSolver
Topic: Adaptive Mesh Refinement
Replies: 8
Views: 985

Re: Adaptive Mesh Refinement

I am having trouble with adaptive meshing. I just reinstalled Elmer from the PPA system. The version is 8.4. I tried to use the Adaptive settings in the GUI but nothing is printed to the case.sif file. This has been a problem for a long time. I had hoped that it would be fixed by now. I manually edi...
by Gary R
06 Apr 2021, 19:45
Forum: General
Topic: Generating visible waves from an acoustic waveguide
Replies: 13
Views: 358

Re: Generating visible waves from an acoustic waveguide

Thanks Peter. Makes sense. I guess the only thing left to do is adjust the mesh for higher frequencies.

Gary R
by Gary R
06 Apr 2021, 03:14
Forum: General
Topic: Generating visible waves from an acoustic waveguide
Replies: 13
Views: 358

Re: Generating visible waves from an acoustic waveguide

OK I'm confused. Attached are two screen shots of the solution at 2000 Hz. One is of the magnitude and the other of the X vector only. The magnitude shows very little in the way of wave motion. The X vector shows strong periodic wave motion and corresponds to the proper number of waves for the 2 m d...
by Gary R
02 Apr 2021, 21:57
Forum: General
Topic: Generating visible waves from an acoustic waveguide
Replies: 13
Views: 358

Re: Generating visible waves from an acoustic waveguide

I am somewhat confused about the dimensions of the problem. I set FreeCAD to meter/Kg/second but entered my dimensions in millimetres. It is my understanding that FreeCAD outputs everything in mm. I assumed that because all constants in Elmer are in M/K/S units that my problem would scale properly. ...
by Gary R
01 Apr 2021, 06:44
Forum: General
Topic: Generating visible waves from an acoustic waveguide
Replies: 13
Views: 358

Re: Generating visible waves from an acoustic waveguide

Hi all; OK. So the Navair Stokes equation is a bad idea. I had to try I one more time. Stubborn I guess. I worry that the Helmholtz equation assumes non compressible conditions which may not be true at higher power levels, especially in the throat. Kevins remark about the size of the throat worries ...
by Gary R
30 Mar 2021, 22:05
Forum: General
Topic: Generating visible waves from an acoustic waveguide
Replies: 13
Views: 358

Generating visible waves from an acoustic waveguide

Hi all; This is a topic switch from the "Helmholts equation errors" post. I decided to switch to a Navier Stokes solver for my acoustic waveguide analysis. I am trying to produce an analysis that shows the propagation of the acoustic wave fronts from an hyperbolic acoustic waveguide. I nee...
by Gary R
30 Mar 2021, 21:07
Forum: General
Topic: Helmholtz equation error
Replies: 10
Views: 436

Re: Helmholtz equation error

Thanks for the replies. I have switched over to a Navier Stokes solver. It seems to make more sense for what I am trying to accomplish. I am starting a new post "Generating visible waves from an acoustic waveguide". The Helmholtz solver seems to give an average pressure over the whole doma...
by Gary R
28 Mar 2021, 20:15
Forum: General
Topic: Helmholtz equation error
Replies: 10
Views: 436

Re: Helmholtz equation error

i seem to have misrepresented my intentions . If you look at the figure, I suspect it represents a valid solution to the problem I presented. This also is what one would expect when compared to the Helmholtz tutorial. What I really wanted to accomplish was a solution that showed multiple wave fronts...
by Gary R
27 Mar 2021, 23:34
Forum: General
Topic: Helmholtz equation error
Replies: 10
Views: 436

Re: Helmholtz equation error

OK I fixed some things but still no joy. Attached is my new SIF file. I think I am having trouble with the Results Solver implementation. With the attached sif file the solver immediately converges, quits and puts out only two .vtu files neither of which contain useful infomation. Could someone way ...
by Gary R
23 Mar 2021, 06:44
Forum: General
Topic: Helmholtz equation error
Replies: 10
Views: 436

Helmholtz equation error

I am having trouble getting my acoustic waveguide simulation to run. Attached is the cif file and a .unv file if anyone wants to load things from scratch (Just run the .unv file through ElmerGrid 8 2 to get an Elmer mesh file). I keep getting the error shown below and don't know how to fix it. There...