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Reynolds Number Check?

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Old   March 18, 2008, 17:59
Default Reynolds Number Check?
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Craig Hildreth
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Let's say I have a problem that I believe is laminar in nature. Is there a way to check the OUT file or set up a monitor to confirm that the Reynolds number was indeed in the laminar regime after the problem runs? Thanks.
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Old   March 19, 2008, 16:20
Default Re: Reynolds Number Check?
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CycLone
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The solver will output a Reynolds number (search for it in the OUT file), but it may not be the one you are looking for. Since the solver doesn't know what your relevant length or velocity scale are, it uses the cube root of the volume as a reference lenght (or the maximum dimension of the bounding box, I can remember for sure) and something like the RMS average velocity as a length scale.

To be certain, you should calculate your Reynolds number in Post using the appropriate velocity and length scales.

Note that if your Reynolds number is large and the flow is turbulent, you'll probably have difficulty converging due to the instability, although if your mesh is coarse the numerical diffusion may damp these out. So this can also be a good indicator.

-CycLone
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