Density-weighted mean kinematic viscosity
= Density-weighted mean kinematic viscosity
{title2=$\bar\nu=\Sigma^{-1}\int\rho\nu\,dz$}
For a vertically stratified <accretion disk> with <surface density> $\Sigma=\int\rho\,dz$, the density-weighted mean <kinematic viscosity> is $\bar\nu=\Sigma^{-1}\int\rho\nu\,dz$. In an <alpha disk> with $\nu=\alpha p/(\rho\Omega)$, this becomes $\bar\nu=\alpha(\Sigma\Omega)^{-1}\int p\,dz$.
// Target: astrophysics.bigb