  A single flexible filament can be actuated to escape from the scallop theorem
and generate net propulsion at low Reynolds number. In this work, we study the
dynamics of a simple boundary-driven multi-filament swimmer, a two-arm
clamshell actuated at the hinged point, using a nonlocal slender body
approximation with full hydrodynamic interactions. We first consider an elastic
clamshell consisted of flexible filaments with intrinsic curvature, and then
build segmental models consisted of rigid segments connected by different
mechanical joints with different forms of response torques. The simplicity of
the system allows us to fully explore the effect of various parameters on the
swimming performance. Optimal included angles and elastoviscous numbers are
identified. The segmental models capture the characteristic dynamics of the
elastic clamshell. We further demonstrate how the swimming performance can be
significantly enhanced by the asymmetric beating patterns induced by biased
torques.
