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Old   July 2, 2007, 02:18
Default Acoustics help
  #1
priya
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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
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Old   July 2, 2007, 19:32
Default Re: Acoustics help
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Glenn Horrocks
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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
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Old   July 3, 2007, 01:59
Default Re: Acoustics help
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priya
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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
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Old   July 3, 2007, 19:29
Default Re: Acoustics help
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Glenn Horrocks
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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
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Old   July 5, 2007, 03:24
Default Re: Acoustics help
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priya
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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.
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Old   July 11, 2007, 19:39
Default Re: Acoustics help
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Glenn Horrocks
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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
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