Nonaccreting constant-torque disk
= Nonaccreting constant-torque disk
{title2=$\bar\nu\Sigma=B r^{-1/2},\quad\mathcal G=3\pi\sqrt{GM_*}B$}
A steady <Keplerian disk> can transport <angular momentum> by viscous stress with zero mass flux. The radial drift vanishes, but the <torque> is constant and nonzero. An inner source and outer sink must supply its boundary angular-momentum exchange. This is distinct from a decretion flow, which transports mass outward.