Faxén's rotational law ($\mathbf{\Omega }=\mathbf{G}/(8\pi \mu a^3)+{\mathbf{\omega }}_{\infty }/2$)

For a sphere of radius $a$ in a slowly varying ambient Stokes flow of vorticity ${\mathbf{\omega }}_{\infty }$, its angular velocity and applied torque obeyat the sphere centre.