[wyldckat]

Greetings Sandeep Patil and welcome to the forum!

Originally Posted by srp1220

Dear wyldckat,

Thanks for the acoustic model implementation in Openfoam, Do you have example of how to solve this model in openfoam?

First, let me stress that I did not do nor develop anything with this acoustic modelling kit. It was done by the people on the group where skeptik works, including skeptik.
I merely started a wiki page at openfoamwiki.net, to help with making this modelling kit more visible to as many people as possible.

Originally Posted by srp1220

If so please share it with me.

When using OpenFOAM, please do not read documents too fast. Every single detail is very important, whether you like it or not. So please read everything very carefully.
I say (write) this because there are already examples in the shared repository, as skeptik wrote a few posts above:

Originally Posted by skeptik

Hi all!

We have uploaded a project on GitHub so you can download it and compile it for the latest release of the OpenFOAM toolkit.

https://github.com/unicfdlab/libAcou...OpenFOAM-3.0.0

We have included baffled-piston case for validation but it's not fully tested yet. If you're interested in validation of the acoustics codes, you're welcome for collaboration.


The present version of the libAcoustics includes only Curle analogy.

Thank You.

Best regards,
Bruno

[rmn_990]

Originally Posted by skeptik

1. Something is released. You can look for it here

Complex online post-processing:
How to implement simple acoustic analogy in OpenFOAM
(Sergei Strizhak, Matvey Kraposhin)

2. I know nothing about acoustics in Fluent or CFX except that using it you can get also wrong results.

Hi
Is here anyone who did an acoustic project in fluent ?
Are you sure that the results in fluent is not correct ?!

thanks

[maHein]

Hello everybody,

I programmed the modified Curle acoustic analogy presented by Larsson et al. [1] as function object for OpenFOAM 3.0.x. The method is implemented for incompressibles flows and includes surface and volume integrals. A validation was performed using the tandem cylinder case (see Lockard [2]).

Source code, validation setup and results can be found in a gitHub repository:

https://github.com/maHein/curleAnalogy

Feel free to contact me if you have any questions or feedback.

Kind Regards,

Martin

edit - I forgot the references:

[1] Johan Larsson, Lars Davidson, Magnus Olsson, Lars-Erik Eriksson: Aeroacoustic Investigation of an Open Cavity at Low Mach Number, AIAA Journal, Vol. 42, No. 12, December 2004

[2] David Lockard: Summary of the Tandem Cylinder Solutions from the Benchmark problems for Airframe Noise Computations-I Workshop. 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition Orlando, Florida, DOI: 10.2514/6.2011-353

[skeptik]

Originally Posted by maHein

Hello everybody,

I programmed the modified Curle acoustic analogy presented by Larsson et al. [1] as function object for OpenFOAM 3.0.x. The method is implemented for incompressibles flows and includes surface and volume integrals. A validation was performed using the tandem cylinder case (see Lockard [2]).

Source code, validation setup and results can be found in a gitHub repository:

https://github.com/maHein/curleAnalogy

Feel free to contact me if you have any questions or feedback.

Kind Regards,

Martin

edit - I forgot the references:

[1] Johan Larsson, Lars Davidson, Magnus Olsson, Lars-Erik Eriksson: Aeroacoustic Investigation of an Open Cavity at Low Mach Number, AIAA Journal, Vol. 42, No. 12, December 2004

[2] David Lockard: Summary of the Tandem Cylinder Solutions from the Benchmark problems for Airframe Noise Computations-I Workshop. 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition Orlando, Florida, DOI: 10.2514/6.2011-353

Can you post final graphs or results simulated vs experimental?

[maHein]

Sorry, for the late replay. You can find a comparison plot in the 'Results' folder on github.

Kind regards

Martin

[mali]

Dear All,

I have tried the libAcoustics solver on flow over a square cylinder. Two microphones are used 1) above the cylinder (M1) and 2) Downstream of the cylinder. Both microphones are 60m from the cylinder.

But, why the sound pressure measured at the downstream cylinder (M2), Pmean is not zero. See figure.

Thanks

-sukri-

[skeptik]

Originally Posted by mali

Dear All,

I have tried the libAcoustics solver on flow over a square cylinder. Two microphones are used 1) above the cylinder (M1) and 2) Downstream of the cylinder. Both microphones are 60m from the cylinder.

But, why the sound pressure measured at the downstream cylinder (M2), Pmean is not zero. See figure.

Thanks

-sukri-

Yea, it seems that we have problems there.

What about version of libAcoustics?

[mali]

Hi Skeptik,

I'm using libAcoustics OF2.3

Thanks.

[skeptik]

Originally Posted by mali

Hi Skeptik,

I'm using libAcoustics OF2.3

Thanks.

Hard to comment.

Did you have downloaded it form UNICFD github? If so, it's better to create issues there.

[mali]

Hi Skeptik,

Yes, I got the solver form the unicfd github.

But I'm not sure if I make the acoustic setting correct. I just add functionobject for libacoustic in the controlDict file. The rest are no change.

-sukri-

[don6alfonso]

Hey,
I would like you to take a look at this please. Maybe you can help me.

libAcoustics, fft not calculate

regards
Adrian

[skeptik]

Originally Posted by mali

Hi Skeptik,

Yes, I got the solver form the unicfd github.

But I'm not sure if I make the acoustic setting correct. I just add functionobject for libacoustic in the controlDict file. The rest are no change.

-sukri-

Did you compiled successfully lib FFTW? It's used in 2.3 version

[a_habib]

Any chance that the new implementation is ready ??

[skeptik]

Originally Posted by a_habib

Any chance that the new implementation is ready ??

You can join to me via GitHub. I'm working on

[Mahe88]

Hello all,

I want to do aeroacoustic analysis of different Wing shapes.Therefore I did some research on that topic and found that thread. As I am quite new to this topic, I want to know, if I understood everything correct.

Regarding the libAcoustic:

1) skeptik and his group (Thank you) developt the libAcoustic, which I can use in OpenFoam 3.0 and calculate the emitted noise with Curls analogy?

2) libAcoustic is used the same way as for example Forcecoeffs? So I calculate the noise while the simulation

3)What simulation types are required to get resonable results? RANS probably not..DES? Can I use Wallfunctions?

Regarding the post processing utilitie noise:

4) I calculate the noise after the simulation?

5) When using the noise utilitie I have to further process the data?! So I could programm a little tool in Matlab etc using curle or FW-H?


Are there recommendations on what is better or makes more sense to use in my case?


Thank you a lot!!

[a_habib]

Dear Mahe88
1 & 2 are correct.
3 if your case is 2D so you can't use but RANS
but if it a 3D case, it's recommended to use something more accurate (DDES, IDDES, LES)
4 no, the library calculates the acoustic pressure after each time step in the locations you had picked, and after Nfft time step, the library calculates the fourier transform to obtain the (SPL vs f)
5 no, you just need to plot your results
Regards

[Mahe88]

Dear Ahmad Habib,

thanks for your response! This helps me a lot to kick off my simulation.

I want to simulate a Wing in 3D therefore I would then try to do a DES. However, I would still label myself as a beginner and this is my first 3D DES simulation with aiming towards noise. Therefore do you have any hints, what I should specifically pay attention to? I assume to use the Pimple solver?

Thanks!

Best regards,
Mahe

[a_habib]

Dear Mahe88

First of all, the analogy used in this library was simplified to be used for the incompressible flows, so you can use the pisoFoam solver correctly

I recommend to stay away from DES, you can use DDES instead or IDDES

Take a special care about the time step and the grid resolution to obtain a good agreement with experimental results or the real live situation

Focus on the theoretical background of the turbulence and the selection of your time step

Best wishes


Sent from my iPhone using CFD Online Forum mobile app

[alireza94]

Originally Posted by skeptik

Hi all!

We have uploaded a project on GitHub so you can download it and compile it for the latest release of the OpenFOAM toolkit.

https://github.com/unicfdlab/libAcou...OpenFOAM-3.0.0

We have included baffled-piston case for validation but it's not fully tested yet. If you're interested in validation of the acoustics codes, you're welcome for collaboration.


The present version of the libAcoustics includes only Curle analogy.

Thank You.

Hi all


@skeptik

in the first i want to Thank you and your team for this Library.

i,m new in openFoam and i want to simulate acoustic in openFoam.

i use your example of cylinder2D and modified it with my version openFoam(4.1) and it work, but it is incompressible. now if i want use it for a compressible example
what i should to do??
just change the solver??
do i need any change in curle or fwh analogy??

[Q.E.D.]

Hi skeptik,



thank you for your work on this library!



The last update was a little while ago. So I just wanted to ask whether the libAcoustics library will eventually be updated to OF5.x?


Best wishes
Q.E.D.