Acoustic basics in Star CCM+
 

Hello to all, I would like to ask you for your help because I want to simulate some acoustic basics in Star CCM+.
I would like to set up the acoustic impulse published as chapter 5 in article Bajko (2014) – but in a little different domain, where the acoustic impulse is set as an initial condition, but it is still challenging for me.

I use CD-Adapco Star CCM+ version 10.04 and shape in the picture below is used as a domain.
http://hasici.zlutava.cz/files/Acoustics/domain.jpg
This should be a rectangular duct which narrows from the bottom in the middle. The boundaries depicted in the left picture are walls and front and back faces are symmetry because of 2D sim (2,5D moreless). I was also thinking if it would not be better to use inlet and outlet for the left and right boundary (in the left view) because it represents duct but finally I did not change it because there is no flow (air velocity is [0; 0; 0]).

Acoustic impulse (or monopole source) should be placed at (-50; 0; 0).
http://hasici.zlutava.cz/files/Acoustics/impulse.jpg
Could you please help me to solve these tasks?

1. I don’t know how to set the acoustic pressure initial condition in this software properly.
2. I don’t know how to input regular monopole source.
3. Do you have any idea how to set the case of acoustic pulse in this software? It is not necessary to use domain I placed here.

I am sorry because I have many questions but when I tried to fix it alone, it didn’t work.

Here is more details about my trials:
This is list of enabled models in CCM+

http://hasici.zlutava.cz/files/Acoustics/models.jpg

As a noise source In Acoustic Wave model “User-Specified Source” or “None” was chosen, when I used User-Specified Source, I entered my function into following scheme:

http://hasici.zlutava.cz/files/Acoustics/ffunc-tree.jpg

The AZone1 has following formulation:

($Time > 0.00005) ? 0 : ${ASource01}

ASource1:
exp(-(log(2)/0.000004)*(pow($$Position[0]-(-0.05),2)+pow($$Position[1]-0,2)+pow($$Position[2]-0,2)))

But the results were different from my expectations, as picture below shows. The Acoustic pressure computed in the wave was too high (more than 1 kPa). As a source was selected monopole source for the pictures below.

http://hasici.zlutava.cz/files/Acous...alar_00501.jpg
http://hasici.zlutava.cz/files/Acous...alar_00701.jpg
http://hasici.zlutava.cz/files/Acous...alar_00901.jpg
http://hasici.zlutava.cz/files/Acous...alar_01101.jpg
http://hasici.zlutava.cz/files/Acous...alar_01301.jpg
http://hasici.zlutava.cz/files/Acous...alar_01501.jpg

Thank you for your help.
Petr