Experimental realization of a hydrodynamic carpet cloak through localized modification of channel cross section

Blockages---common in pipelines, microchannels, and vascular networks---dramatically disrupt laminar flow, amplify energy dissipation, and threaten system efficiency, posing a critical challenge across industrial and biomedical domains. Current hydrodynamic metamaterial solutions frequently employ viscosity tuning, an approach that faces challenges due to stringent precision requirements and limited operational flexibility. We experimentally demonstrate a paradigm shift: a geometric carpet cloak that restores undisturbed flow profiles and eliminates the blockage-induced pressure drop across diverse flow conditions and blockage geometries, without any need to adjust material parameters. Our design approach enables advanced hydrodynamic metadevices, such as flow splitters and combiners, that can partition liquids while rapidly restoring a uniform, parallel downstream flow profile. This flow-collimating capability is crucial for creating densely packed, low-crosstalk microfluidic circuits. Our work connects metamaterial theory to practical liquid engineering, offering new strategies for high-fidelity flow management and flow-field engineering.