Permeability-driven meta-structures for passive flow control in porous bluff-body configurations

Metamaterials for flow control have recently attracted significant interest due to their ability to passively manipulate flow structures across a range of engineering applications. Inspired by classical electromagnetic metamaterials, where permeability and permittivity serve as governing parameters, this study experimentally explores the feasibility of a permeability-driven framework for flow control using structured porous media. Such meta-structured media are relevant to aerospace, future mobility, wind energy, and marine engineering, where passive strategies enable enhanced aerodynamic or hydrodynamic performance and reduced acoustic emissions.

In this work, we investigate a simplified two-dimensional porous bluff-body configuration to systematically isolate the role of permeability. A family of lattice-based porous cylinders is designed to independently and systematically control permeability, allowing it to be treated as an equivalent material property governing wake dynamics. Through controlled variations in both directional and isotropic permeability, we examine changes in aerodynamic performance and downstream flow structures by force and PIV measurements. The results show that permeability-tuned porous structures can effectively manipulate flow behavior and the associated aerodynamic forces, offering a fluid-mechanical extension of metamaterial concepts traditionally confined to wave-based domains.