 Far-field orbit average of a tangent stresslet

A stresslet whose centre follows a circle and whose director stays tangent has a leading far-field mean stresslet centred at the circle centre. Orientation averaging of an axisymmetric stresslet gives normal-axis strength $-S/2$. Thus a pusher microswimmer becomes a leading mean puller microswimmer, and conversely. The radius and traversal frequency enter higher-order spatial corrections or averaging time, but not the leading dipole strength.