Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Acoustic within "eigenmodes of a room"

Adrian Heinisch Urban Design (TUM)

Please login with a confirmed email address before reporting spam

Hi,

I need some help in comsol.

I am working in the default project "eigenmodes_of_room" and created an additional "normal velocity" boundary with 0.1 inward velocity. Then i added an "impedance" boundary, set the "impedance model" to Absorption Coefficient and set the Absorption Coefficient of the ceiling and walls to 1 to simulate a non-reflective boundary. In the end i added a study 2 frequency domain.

Here my questions, i guess rather understanding-the-program-better-questions:

  1. Since the sound pressure level plot in the results shows me dB-values from ca. 50 to ca. 120; what is the exact velocity of the initial sound wave? Is it 120 dB at all frequencies?

  2. How can I exchange the "normal velocity" boundary with a "plane wave radiation"/"spherical wave radiation" boundary? Im getting no results when Im doing this.

  3. Is it possible to configure the initial sound wave (normal velocity boundary) to for example 50 Hz with 80dB, 200 Hz with 74dB, 500 Hz with 83 dB etc? So a specific loudness for every single frequency?

  4. Since I can define the impedance of specific boundaries - How is it possible to assign a material on a boundary (wall in the model) which has specific material properties, e.g. the absorption coefficient at 1000Hz = x, etc?

Best,

Adrian


0 Replies Last Post May 12, 2020, 12:45 p.m. EDT
COMSOL Moderator

Hello Adrian Heinisch

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.