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Impinging jets - Secondary maxima issue

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Old   February 6, 2004, 01:48
Default Impinging jets - Secondary maxima issue
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John
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Hi,

I am trying to simulate 2D slot and 3D square impinging jets(free and confined) with FLUENT. At low nozzle-to-plate spacings and at high Re(say H/W<2, Re_W>10000), experimental data shows an off-center peak in the skin-friction factor and Nu profiles. I tried all the k-eps and RSTM cases (steady) with the standard and enhanced wall functions, but cannot capture those secondary peaks. The nozzle exit BC's are 1-10% turbulent intensity and a turbulence length scale of 0.07W. I also tried the case with fully developed turbulent flow between two parallel plates in the case of slot jets(using k and eps profiles obtained from the flow between parallel plates at the nozzle exit) as the nozzle-exit condition but didn't work either. Any suggestions? Will unsteady simulations help?

Thank you in advance.

John

p.s. Is there anybody running LES using Smagorinsky model and getting good agreement?
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Old   February 6, 2004, 02:32
Default Re: Impinging jets - Secondary maxima issue
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andrew
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the secondary peaks in the Nu profile are due to turbulence generation and are not picked up by the standard models. there is an extra turbulence model available, the v2f model, which is designed to correctly model impinging jets. (this requires an extra licence, for a fee). I am in the process of getting this model at the moment, so i don't know how well it works.

Have you tried the LES model, i would like to know if this works. (at the moment i am doing 2d models so i can't use it)

some links for the v2f model are

http://www.turbulentflow.com/

http://www.fluent.com/software/fluen...turbulence.htm

regards andrew
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