An error bound for the slender body approximation of a thin, rigid fiber sedimenting in Stokes flow

We investigate the motion of a thin rigid body in Stokes flow and the corresponding slender body approximation used to model sedimenting fibers. In particular, we derive a rigorous error bound comparing a regularized version of the rigid slender body approximation to the classical PDE for rigid motion in the case of a closed loop with constant radius. Our main tool is the slender body PDE framework established by Mori et al. (Commun Pure Appl Math, 2019. https://doi.org/10.1002/cpa.21872; Arch Ration Mech Anal 235(3):1905–1978, 2020), which we adapt to the rigid setting.