Disc-traction analogy for an interfacial current
= Disc-traction analogy for an interfacial current
<Linearity of Stokes flow> and <Uniqueness of Stokes flow> identify the ambient resistance to an expanding thin plug with the reversed perturbation around a stationary disc in an axisymmetric straining flow. The imposed straining flow has zero tangential stress on the disc plane. Each face then resists radial velocity $Er$ with <traction> $-8\mu Er/[\pi\sqrt{R^2-r^2}]$.