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-   -   Wall Acoustic pressure prediction on a flat plate using ffowcs-williams & Hawkings (http://www.cfd-online.com/Forums/fluent/89932-wall-acoustic-pressure-prediction-flat-plate-using-ffowcs-williams-hawkings.html)

 maxkcng June 26, 2011 13:16

Wall Acoustic pressure prediction on a flat plate using ffowcs-williams & Hawkings

Dear all,

I am new graduate student and currently working on my thesis title as stated above. However, I been stuck on an issue for several months. hope some of you might have some ideas or experiences to share with me. currently i had been assigned to investigate the pressure fluctuation on a 3D flat plate with the dimension of 0.5 x 0.08 m^2 plate surface area and at Mach number of 0.7.
i try to impliment the method used in the tutorial
into my model, however, i get a constant pressure(straight line) instead of pressure fluctuation(wave fluctuation pattern).
i tried to clustering my mesh more toward the wall(last distance from wall => 1e-6 m), while maintaining the aspect ratio lesser than 100, but still all i get is straight line.
in addition to that, i try to use different turbulent scheme other than LES, (like DDES,k-e,k-w etc) but still can't get the fluctuation.

i wonder do any one face the same problem? appreciate if you guy can leave some commend over here.

max

 maxkcng June 30, 2011 11:40

guyz,

i manage to find the way to simulate that, if you doing the same case as me, i hope it does help.
what i do is activate the LES model in my fluent, then switch boundary condition inlet to "velocity inlet" after that under "fluctuating velocity algorithm" choose "spectral synthesizer" and remain the rest as default.

and you will get a sweet wave fluctuating output like what it suppose to get.and this spend me like 2~3 months to find it out.
let me knw if you like to know more. i hope this can save ur 2~3 months.

best wish guy..

Max:D
http://www.cfd-online.com/Forums/ima...es/biggrin.gif

 andi136 October 11, 2012 02:25

Hi, Max.

Would you mind to share your acoustic simulation by using LES turbulence model? I'm interested in it, but I don't know where to start.

My object is acoustic pressure prediction in pipe flow.

Thank you, before.

Andi

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