Discussion Forum

Hello!

Does anyone have experience with outdoor sound propagation in Comsol. I have been experimenting with a couple of scenarios in 2D with one windmill and 10 "houses" at a distance, and I was wondering if anyone out there has done anything similar.

My main concerns revolve around the meshing, possible use of PML's and how to specify the source strength. I have so far only made the model with a triangular mesh with maximum size \lambda / 5 = 0.689 (solving for 100Hz and lower), no use of PML's (due to lack of experience in using them successfully) and I simply specified the blades to be plane-wave radiators. I have also specified a grass field using a macroscopic-porous-media model with Delany-Bazeley constants (perhaps Miki would be in order?), data was taken from table 2 p.310 Handbook of Acoustics by Malcolm&Crocker.

I would like to add some kind of periodicity to the output power as the blades do revolve at a certain (fixed) speed and I suspect this might be achievable using an exponential function i.e. p_{hat}exp(-j(\omega*t)) where \omega is the angular frequency of the blades.

Other future work to be considered would be adding temperature gradients to the air and wind (how would one simulate wind? excess pressure coming in from the side perhaps?)

I include my model file in case you wish to experiment yourself and perhaps have some useful input. Regarding the model, the meshing takes some time but solving the model takes about 1min on my 8Gb SSD 2.8Ghz i7 Dell engine.