  We leverage the snap-through response of a bistable origami mechanism to
induce a discontinuous evolution of drag with flow speed. The transition
between equilibrium states is passively actuated by airflow, and we demonstrate
that large shape reconfiguration over a small increment of flow velocity leads
to a pronounced and sudden drop in drag. Moreover, we show that systematically
varying the geometrical and mechanical properties of the origami unit enables
the tuning of this drag discontinuity and the critical speed and loading at
which it occurs. Experimental results are supported by a theoretical
aero-elastic model, which further guides inverse design to identify the
combination of structural origami parameters for targeted drag collapse. This
approach sheds light on harnessing origami-inspired mechanisms for efficient
passive drag control in a fluid environment, applicable for load alleviation or
situations requiring swift transitions in aerodynamic performances.
