= Even displacement correction in an orbit-averaged stresslet
{title2=$\langle\mathbf u\rangle-G_{\rm eff}=O(SR^2/(\mu r^4))$}
Opposite points on the orbit have opposite displacement and the same stresslet director up to sign. Their paired fields are $[G(\mathbf r-R\mathbf p,\mathbf e)+G(\mathbf r+R\mathbf p,\mathbf e)]/2$, so odd displacement powers cancel. Since a <stresslet> decays as $r^{-2}$, the first correction to its <far-field orbit average of a tangent stresslet> is $O(SR^2/(\mu r^4))$. The finite-radius mean need not be an exact point stresslet.
Back to article page
