Re: Image-source model with consideration of air absorption

[William Hartmann <hartmann@xxxxxxxxxx>]

Junfeng, Emmanuel,

In a Green's function formulation, absorption can be included by adding 
a small imaginary part to the wave number or propagation vector k.

Bill

Emmanuel Vincent wrote:
> The URL http://www.irisa.fr/metiss/members/evincent/Roomsimove.zip is 
> correct.
>
> I don't know about the Green function but you can read it from the code.
>
> Emmanuel
>
>
> On 11/22/2011 11:57 AM, Junfeng Li wrote:
> > Dear Emmanuel,
> >
> > Thanks a lot for your information.
> > I found that Roomsim (http://media.uws.ac.uk/~campbell/Roomsim/) 
> > implemented this function. your Roomsimove cannot be found from the 
> > URL that you provided below. Could you check it again?
> >
> > My another concern is what the Green function ï exp(jwd/(4*pi*d) ï 
> > in the free field should be when it is extended when considering the 
> > air absorption effect?
> >
> > Do you have any idea? or references on this issue?
> > ïThough I believe it is a very easy question, I cannot find the 
> > answer, ....)
> >
> > Thanks a lot again.
> >
> > Cheers,
> >
> > Junfeng
> >
> >
> >
> > On 11/11/22, Emmanuel Vincent<emmanuel.vincent@xxxxxxxx>  wrote:
> >
> > > Dear Junfeng,
> > >
> > > Roomsim (http://media.uws.ac.uk/~campbell/Roomsim/) as well as our 
> > > command-line software Roomsimove (for moving 
> > > sources)(http://www.irisa.fr/metiss/members/evincent/Roomsimove.zip) 
> > > account for this.
> > >
> > > Emmanuel
> > >
> > > --
> > > Emmanuel Vincent
> > > METISS Project-Team
> > > INRIA Rennes - Bretagne Atlantique
> > > Campus de Beaulieu, 35042 Rennes cedex, France
> > > Phone: +332 9984 2269 - Fax: +332 9984 7171
> > > Web: http://www.irisa.fr/metiss/members/evincent/
> > >
> > >
> > > On 11/22/2011 11:28 AM, Junfeng Li wrote:
> > > > Dear list,
> > > >
> > > > I am now considering to generate room impulse response (RIR) using 
> > > > the well-known image-source method. However, I found that the 
> > > > traditional image-source method only considered the absorption of 
> > > > enclosure surfaces, without the consideration of air absorption. 
> > > > However, the air absorption should be also an important factor 
> > > > which affect the simulated RIR.
> > > >
> > > > To reformulate the image-source method, the Green function ï 
> > > > exp(jwd/(4*pi*d) ï in the free field should be extended to that 
> > > > with the consideration of air absorption effect. I searched this 
> > > > problem for some days. However, I did not find any reference.
> > > >
> > > > Could anyone point some references on this issue or the (source 
> > > > code of) improved image-source method that implemented this idea?
> > > >
> > > > Thank you so much in advance.
> > > >
> > > > Best regards,
> > > > Junfeng