Topological Design of Porous Structures for Flow Control: A Design-by-Morphing Approach

Previous work shows that streamwise-preferential porous materials can serve as a viable solution to reduce drag in wall-bounded turbulent flows or to minimize drag penalties in multifunctional flow control applications, e.g., thermal management and noise suppression. In addition to bulk anisotropic permeability, the specific interfacial geometry plays a critical role by modulating the effective slip length of the streamwise mean flow. However, the exact porous geometry required to realize such properties remains unclear, motivating diverse and systematic topological design exploration. To address this, we present a morphing-based design framework leveraging Design-by-Morphing (DbM), which generates intermediate and extrapolated designs between typical porous geometries. Using DbM, we explore a wide range of candidate designs while ensuring feasible topologies. In this initial phase, we validate our framework via a small-scale optimization targeting unit porous cells for enhanced permeability and interfacial area using direct numerical simulations at a unit Darcy–Reynolds number. A data-driven optimization loop identifies optimal designs, ranging from isotropic to anisotropic cases. These results lay the groundwork for future integration with turbulent channel flow analysis involving perforated surfaces or porous substrates with experimental validation.