CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

FW-H Acoustic Module - Suitable for Internal Flow Aeroacoustics?

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   September 27, 2016, 14:57
Question FW-H Acoustic Module - Suitable for Internal Flow Aeroacoustics?
  #1
New Member
 
Jobin
Join Date: Sep 2016
Posts: 5
Rep Power: 2
Poompil is on a distinguished road
My master's work deals with modelling the aeroacoustic noise generation in a "muffler type structure" - that is, with one input into an enclosed space with only one outlet.

I'm trying to determine the noise levels at far-field locations.

First off, is the FW-H analogy suited to a problem like this?
Does it make sense to use the "interior" type source surface (as defined in Fluent's Acoustic Module) when defining the walls of the muffler, and then place receivers in far field locations?

I'm very new to all this, and any insight into acoustic analogy and modelling is appreciated.

Thanks,
Jobin
Poompil is offline   Reply With Quote

Old   October 27, 2016, 09:51
Default FW-H Acoustic Module - Suitable for Internal Flow Aeroacoustics?
  #2
New Member
 
Abhijit Deshpande
Join Date: Jan 2014
Location: Bangalore
Posts: 3
Rep Power: 5
ab.glb.cfd is on a distinguished road
Dear Poompil,

FW-H Analogy can be applied even for internal flows.

There are articles;

1."Aero Acoustic Noise Analysis of a Locomotive Cooling System Ducts and Structure Optimization" published.

2."On the use of the Ffowcs Williams-Hawkings equation to predict far-field jet noise from large-eddy simulations" published.

From my experience, the analogy is more helpful for flows exiting into quiescent atmosphere and to analyze far-field noise spectra > 1 m distance.

I prefer DES/LES simulation for muffler/expansion chamber flow noise analysis, identify the source locations and finally FFT's of PSD and SPL at monitoring points and/microphone locations.

Hope my description helps you clear few things.

Revert to my personal e-mail ID: ab.gulbarga@gmail.com if you need more details.

All the best!

Regards,
Abhijit
ab.glb.cfd is offline   Reply With Quote

Old   November 7, 2016, 23:41
Default
  #3
New Member
 
Jobin
Join Date: Sep 2016
Posts: 5
Rep Power: 2
Poompil is on a distinguished road
The workflow you suggested makes sense to me and it is in fact what I have already adopted.

Thanks for the references - I have taken a quick look at them and it seems promising.

If I were to use FWH to calculate the SPL on the internal surface of my enclosed space, would I be able to extrapolate that to a far field noise value simply using breakout noise?

Regards,
Jobin
Poompil is offline   Reply With Quote

Old   November 8, 2016, 23:04
Default
  #4
New Member
 
Abhijit Deshpande
Join Date: Jan 2014
Location: Bangalore
Posts: 3
Rep Power: 5
ab.glb.cfd is on a distinguished road
Breakout noise is more of vibro-acoustics or Aero-vibro-acoustics...

What is that you are planning to evaluate? Flow induced noise due to shell vibrations or pure flow/turbulence induced noise?

FW-H analogy in principle is a Green's function extrapolation to extract noise spectrum considering flow sources at a rigid or imaginary (permeable) surface.

It is suited for pure flow noise and not for vibro/aero-vibro-acoustics.

For breakout noise, coupling is required (transient flow solution + harmonic/acoustic calculation)

Hope my comments helps.
ab.glb.cfd is offline   Reply With Quote

Reply

Tags
acoustic analogy, aeroacoustics, fw-h, muffler

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Gate valve flow simulations... nikesh FloEFD, FloWorks & FloTHERM 5 January 28, 2014 02:31
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 21:31
Flow visualization vs. Calculated flow patterns Francisco Saldarriaga Main CFD Forum 1 August 2, 1999 23:18
Question on 3D potential flow Adrin Gharakhani Main CFD Forum 13 June 21, 1999 05:18
computation about flow around a yawed cone Tylor Xie Main CFD Forum 0 June 9, 1999 07:33


All times are GMT -4. The time now is 09:15.