Hydrodynamic mobility matrix
= Hydrodynamic mobility matrix
{title2=$\mathbf U=\mathsf M\mathbf F$}
With a consistent force convention, the mobility matrix maps applied generalized forces to rigid-body velocities; it is the inverse of the <hydrodynamic resistance matrix>. For a sphere with force on the fluid $\mathbf F$, its isolated mobility is $1/(6\pi\mu a)$. Coupling between bodies represents <hydrodynamic interactions>.