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8.4.3 Defining the Viscosity Using Kinetic Theory

If you are using the gas law (as described in Section  8.3), you have the option to define the fluid viscosity using kinetic theory as


 \mu = 2.67 \times 10^{-6} \frac{\sqrt{M_w T}}{\sigma^2 \Omega_{\mu}} (8.4-9)

where $\mu$ is in units of kg/m-s, $T$ is in units of Kelvin, $\sigma$ is in units of Angstroms, and $\Omega_{\mu} = \Omega_{\mu} (T^{*})$ where


 T^{*} = \frac{T}{(\epsilon/k_B)} (8.4-10)

The Lennard-Jones parameters , $\sigma$ and $\epsilon/k_B$, are inputs to the kinetic theory calculation that you supply by selecting kinetic-theory from the drop-down list to the right of Viscosity in the Materials panel. The solver will use these kinetic theory inputs in Equation  8.4-9 to compute the fluid viscosity. See Section  8.13 for details about these inputs.


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