Emergent oscillations and chaos in noncompliant microfluidic networks

Microfluidic systems have traditionally relied on external hardware or compliant structures to generate flow rate oscillations. Here, we demonstrate that persistent oscillations and even chaotic behavior can spontaneously emerge without external modulation, deformable structures, or fluid compressibility. Through a combination of numerical simulations and a reduced model, we uncover a mechanism governed by fluid inertia that drives this behavior at moderate Reynolds numbers. These findings expand the design space for on-chip flow control and reveal new opportunities for microfluidic timing, precision control, and chaos-based applications.