Reconfigurable kirigami mesostructure enables modulation of lift and drag

TL;DR

This study demonstrates that kirigami-patterned surfaces can be reconfigured to modulate aerodynamic forces like lift and drag, offering a scalable, tunable platform for passive flow control.

Contribution

It introduces a simple kirigami design that transforms into 3D porous structures under flow, enabling reversible control of aerodynamic forces with a continuum elastic model.

Findings

Kirigami sheets generate significant lift and drag forces when buckled in flow.

Reconfigurable mesostructures can decouple and tune lift and drag forces.

Force scaling depends on the Cauchy number, linking stiffness to aerodynamic behavior.

Abstract

Flexible surfaces can modulate fluid forces through deformation, enabling passive adaptation to flow conditions. Here we show that kirigami sheets, planar surfaces patterned with arrays of parallel slits, provide a simple route to tunable aerodynamics by transforming into three-dimensional porous meso-architectures that can be reversibly reconfigured in flow. When exposed to crossflow, parallel-cut kirigami buckle out of plane to form a lattice of inclined plate-like elements. Experiments reveal that this architecture generates not only drag but also a substantial transverse lift force, even when the sheet is held perpendicular to the incoming flow. Because the mesostructure can switch between distinct states, a single sheet produces large and selective variations in drag and lift under identical flow conditions, in some cases partially decoupling these forces. The evolving mesostructure also alters the scaling of forces with flow speed, influencing both instantaneous loads and their velocity dependence. Force measurements collapse when expressed in terms of the Cauchy number, identifying stiffness, set by the cutting pattern, as the dominant control parameter, a relationship captured by a continuum elastic model. These results show how kirigami architectures encode aerodynamic functionality and behavior directly through their structure, providing a scalable platform for surfaces with reprogrammable fluid forces.