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October 30, 2007, 01:25 
Dear All
Is OpenFOAM suitab

#1 
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Guillaume Alleon
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Dear All
Is OpenFOAM suitable for exterior acoustics problem ? Is there some examples describing this ? Cheers Guillaume 

October 30, 2007, 04:44 
Hi Guillaume,
If you mean pur

#2 
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Takuya OSHIMA
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Hi Guillaume,
If you mean pure linear acoustics (not aeroacoustics), I'm using it for acoustics, but for interior problems. The reason I use OF only for interior problems is that as of now I don't have a good nonreflective boundary condition code. If we have a good nonreflective b. c. I'm sure OF can also be a powerful tool for exterior acoustics. What kind of exterior problems are you interested in? Takuya 

October 20, 2008, 14:28 
Hi Takuya
I need to develo

#3 
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Nishant
Join Date: Mar 2009
Location: Glasgow, UK
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Hi Takuya
I need to develop a nonreflective boundary condition for aeroacoustic low mach number problem. I am planning to write a code for nonreflective boundary condition. How difficult it could be? Is there anything similar to this going on in this community? I searched the forum and just find your work somewhat relevant. Could you please guide me how to do it? I know C++ quite well but I need to understand the structure of the relevant section of the code well. regards, Nishant
__________________
Thanks and regards, Nishant 

October 20, 2008, 21:28 
Hi Nishant,
As I'll just be

#4 
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Takuya OSHIMA
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Hi Nishant,
As I'll just be starting next month some works w.r.t. low mach number (very low, Ma < 0.1) exterior sound propagation I'm also now looking for literature about nonreflective boundary conditions that look promising for finitevolume unstructured grids. So in fact your question is my question too Do you have any interesting literature about it? So far I only have a b.c. that is useful only for predefined incidence vectors (convectiveOutlet). Looking through this forum Ivan Flaminio Cozza seems to be trying to solve linearized Euler equations with PML so I guess he could share our interest too? Takuya 

October 21, 2008, 02:48 
Hi,
Have any of you guys tr

#5 
Member

Hi,
Have any of you guys tried the waveTransmissive boundary condition in OpenFOAM? It has worked quite well for me for low mach number vortex induced accoustics(Ma = 0.10.2) using compressible solvers. Regards /Eric 

October 21, 2008, 03:02 
Hi guys!
Just yesterday I suc

#6 
Senior Member

Hi guys!
Just yesterday I succeeded in coding a PML boundary condition for the Linearized Euler Equation, so now I think the real big problem for aeroacoustics in OF are the high order non dispersive schemes. Did someone have allerady do some work in it? I'm having a look around for some DRPFV schemes, but all of these are for structured grid, with a large stencil, it's possible to reproduce it in OF? Have a nice day, Ivan 

October 21, 2008, 06:34 
Hi,
@Eric: Thanks for the s

#7 
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Takuya OSHIMA
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Location: Niigata City, Japan
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Hi,
@Eric: Thanks for the suggestion. However as far as I understand from the code I guess it also has strong dependence in acoustic wave incidence directions, which is not good for my case. If I go that way I would at least have to find a way to properly tweak the sqrt(gamma_/psip) term. But can't be said for sure, anyhow I will test it. @Ivan: I also had a bit of interest in such schemes around a year ago but just gave up after having had exactly the same problem. Now I'm interested in what you'll find...! Takuya 

October 21, 2008, 10:53 
Takuya,
what kind of schemes

#8 
Senior Member

Takuya,
what kind of schemes are you using in your LEE computation now? I've just finished the LEE solver, and I'm doing some classical benchmark case like the gaussian pulse and the monopole, and I'm usin gauss linear scheme, if I try wit gauss cubic (that should be 4th order, if I've understood), there are big ossilations and the solution are not symmetrycal. So I think that some High Order Scheme implementation is the next step for doing CAA in OpenFOAM... 

October 21, 2008, 14:06 
@takuya..
Its nice to know th

#9 
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Nishant
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@takuya..
Its nice to know that somebody is already working on the same area and also have the same motivtion to work on. Hope we can find out a way to go ahead. I have downloaded some article on nonreflective boundary condition. I have some articles on NSCBC (nav stoke charc. bound. condn) and their implementation to some practical problems. If you need them then let me know, I will send it to ur email. @Ivan: PML also seems to be interesting. I would be interested to see how it could be implemented to OpenFoam. I would be glad if you like me to investigate some part of your problem. i will definitely need some directions from you to start with. regards, Nishant
__________________
Thanks and regards, Nishant 

October 22, 2008, 04:05 
Hi,
@Ivan: At this stage ev

#10 
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Takuya OSHIMA
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Hi,
@Ivan: At this stage everything is still preliminary (I still do not have a working solver). Though what is somewhat clear is that, as in my case the mach number is very very low I'm planning to use a simplified form of LEE assuming adiabatic and barotropic field [1]. If it is to be implemented in a finitedifference staggered mesh it will most likely be a trivial task that can be done with 2nd order schemes [2]. But I'm still not sure how it should be implemented in finitevolume unstructured and collocated system. There may be a chance I also need such high order schemes. @Nishant: Ivan showed some interesting hints in another thread. I think the thread can be of help to you as well. [1] R. Blumrich and D. Heimann, J. of Acoustical Society of America, 446, 2002 [2] T. Van Renterghem and D. Botteldooren, Applied Acoustics, 201, 2007 

October 27, 2008, 03:04 
Hi,
@Takuya: Why are you in

#11 
Senior Member

Hi,
@Takuya: Why are you interested in using staggered grids for LEE? I didn't ever see any staggered implementation of LEE, it seems that collocated grids works fine! I'm taking a look on some FV high order schemes, but everyone of those requires some access to a big stencil, so, I'm doubting that it should be fine for OF. In alternative, I'm thinking on Discontinuous Galerkin, but it should be necessary to implement a FEM framework, so it can be very hard to do... Cheers, Ivan 

October 29, 2008, 02:53 
Hi Ivan,
@Staggered grid: it'

#12 
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Takuya OSHIMA
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Hi Ivan,
@Staggered grid: it's a story about finite difference solvers so we FOAMers might just have to forget about it. I'm now attending a conference and had a chance to talk to a person who is doing aeroacousics. The story was roughly the same as discussed here... She said she is sticking on generalized curvilinear structured grid because of larger stencil required for higher order schemes. Takuya 

October 29, 2008, 03:34 
Ok, all the same stuff...
I'v

#13 
Senior Member

Ok, all the same stuff...
I've read about some High Order DRP FVM schemes, but they're based on generalized curvilinear structured grids, and with large stencil, and we're thinking on trying it in OpenFOAM, maybe generating a separate "big stencil" connectivity, but it's quite an hacking. The other possibility is trying with DGM, but it's necessary to introduce internal degree of freedom and shape functions, so it's definitely an hacking! 

May 11, 2009, 10:03 
OpenFOAM and acoustics  need help in C++ programming

#14 
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Wolfgang Heydlauff
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Location: Germany
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Hi everyboy,
I also want to do some acoustic investigations an airflow around some geometries. In literature (fluent user guide) I have found the very simple equation that calculates the "acoustic power" due to the vorticity. The equation is P = alpha * rho * epsilon * ( sqrt(2 * k) / c ) ^ 5with this easy equation it should be possible to calculate at least the sound source intensity. Therefore one needs to calculate the equation using the k and epsilon output of OpenFOAM. And here I need some help of C++ feasible people: I do have no experience of using C++. How could the source code look like, that reads out the k and epsilon file of the timestep directoriy and calculates it with the mentioned equation. Then it should output some files that give the acoustic power of each cell. please help me. I cozuld think, that for a C++ guy it is a very easy stuff to do. However, I myself have no clue. Thanks. 

September 3, 2009, 15:55 
@takuya

#15 
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Nishant
Join Date: Mar 2009
Location: Glasgow, UK
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Which solver do you guys are using for low mach number flow in openfoam?
I am trying to build a sub sonic PISO based algorithm to solve low mach number flow. I want to make a comparision of both the codes. Could you please tell me which code in openfoam are you using? regards, Nishant 

May 25, 2010, 08:07 

#16  
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Alisina
Join Date: May 2010
Location: germany
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Quote:
im new in OF and im working since 2 weeks on this problem, have you any advice for me? regards ali 

May 28, 2010, 05:51 

#17  
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Bernhard Linseisen
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Quote:
For the case you have access to some interloanthingy, you might try to find it Actually, the OPAC (library catalogue) of the state library at Munich seems to have some books and theses on that topic. Might be of interest as well for you. The link to that is http://www.bsbmuenchen.de Hope it helps a little bit... 

May 27, 2011, 00:13 
Aeroacoustics in OpenFOAM

#18 
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Brent Craven
Join Date: Mar 2009
Location: University Park, PA, USA
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Hi all,
This thread is a bit old. But, what is the status of anyone's efforts of aeroacoustics in OpenFOAM? Specifically:  What solvers are folks using for acoustics?  Any updates on higherorder schemes or attempts at Discontinuous Galerkin? 

March 27, 2013, 10:33 
OpenFOAM acoustics

#19 
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Hasan K.J.
Join Date: Dec 2011
Location: Bristol, United Kingdom
Posts: 188
Rep Power: 5 
Hey,
is there any body who has a successfully done acoustics using openFOAM, and my second doubt will be is there any chance to take the results from openFOAM to fluent to the acoustics for the flow, thanks Hasan. 

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