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Old   May 12, 2005, 04:53
Default grid ressolution
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Hello every body, i have some problem with my results. I did 3D DNS of the diffussion flame. in that i would like to know whether scalar dissipation rate is well ressolved or not? what is the test to verify it? i calculated Kolmogorov scale , ressolution is roughly comming around 12 times the kolmogorov scale.. but i would like to know is there any other way of checking of my results. thanykyou in advance
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Old   May 12, 2005, 12:41
Default Re: grid ressolution
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You are calculating scalar dissipation rate. For scalars, the smallest length scale is the Batchelor scale. If Schmidt number, Sc=1, then the Batchelor scale is on the same order as Kolmogorov scale. For Sc>1, the Batchelor scale will be smaller than the Kolmogorov scale and can be approximated by the relation,

LB ~ Sc^(-0.5)*LK

LB = Batchelor scale Sc = Schmidt number = kinematic viscosity/molecular diffusivity LK = Kolmogorov scale

To resolve the scalar dissipation rate, you should be close to Batchelor scale and in case Sc > 1, a resolution of 12 times Kolmogorov scale will not be sufficient.
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