CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Acoustics help

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 2, 2007, 01:18
Default Acoustics help
  #1
priya
Guest
 
Posts: n/a
sir,

Water is flowing through some length of pipe.The sound has to be given as an input and as the water flows the sound is absorbed by the water.

how to approach this problem???

It would be appericiated if i could have a valid response over it.

thank you
  Reply With Quote

Old   July 2, 2007, 18:32
Default Re: Acoustics help
  #2
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Are you trying to model sound attenuation in water? My small knowledge of acoustics tells me water has very low attenuation, that's why whales call to each other over kilometres in the ocean.

I think you need to explain what you are trying to do a bit better.

Glenn Horrocks
  Reply With Quote

Old   July 3, 2007, 00:59
Default Re: Acoustics help
  #3
priya
Guest
 
Posts: n/a
Its a pipe of nearly 1/16 inch radius pipe.The sound frequency at the inlet is 30-40kHz and at some distace from the inlet the pipe experts a externally induced acoustics .

So how to determine the physics of the problem
  Reply With Quote

Old   July 3, 2007, 18:29
Default Re: Acoustics help
  #4
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

You still have not explained what you are trying to do. You can give water some compressibility and that will allow it transmit sound waves. This will allow you to model the sound wave directly.

Glenn Horrocks
  Reply With Quote

Old   July 5, 2007, 02:24
Default Re: Acoustics help
  #5
priya
Guest
 
Posts: n/a
Sorry the input of sound waves have to be given opposite to the flow direction. The sound waves after traversing its amplitude dies. i just want to determine the amplitude variations from its start to end.
  Reply With Quote

Old   July 11, 2007, 18:39
Default Re: Acoustics help
  #6
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

I have done some modelling of high-speed hydraulic oil circuits where the compressibility of the oil causes acoustic waves in the flow. This is easily done by making the oil density a function of pressure. This function can be calculated from the bulk modulus of the fluid.

Whether that gives you an accurate modelling of the sound attentuation - I have no idea. It was not important for my simulation so I did not check it. You will have to do your own validation for that.

Glenn Horrocks
  Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
urgent!!! surface dpdt values in acoustics samad87 FLUENT 0 August 31, 2009 23:53
How to solve acoustics ? wolle1982 OpenFOAM Running, Solving & CFD 8 May 18, 2009 04:20
Unsteady modelling - AMG divergence + acoustics Neville FLUENT 0 September 3, 2004 00:21
Acoustics in Fluent Nurul Murad FLUENT 0 April 1, 2004 22:11
Acoustics Problems and Fluent Dezfuli FLUENT 1 February 10, 2002 15:59


All times are GMT -4. The time now is 20:34.