Force-dipole flow
= Force-dipole flow
{title2=$\mathcal P$}
The leading far field of many force-free microswimmers is an axisymmetric force dipole, or stresslet,
$$
\mathbf u(\mathbf r)=\frac{\mathcal P}{8\pi\mu}
\left[\frac{3(\mathbf p\mathbin\cdot\mathbf r)^2}{r^5}-\frac1{r^3}\right]\mathbf r.
$$
= Stresslet
{synonym}