Characterization of Periodic Lattice Anisotropic Porous Materials for Passive Flow Control

Characteristics of flow through anisotropic porous materials (APMs) with periodic lattice microstructures are investigated. Periodic cubic lattice samples are designed with various projected area porosities along the principal axes of the sample. Isotropic porous lattices of comparable porosities are designed as well, as a mechanism for further validating APM data and use of the data analysis model used here. One-inch cubic samples are fabricated using stereolithography printing and installed at the end of a long square duct capable of producing fully developed laminar flow up to Re = 2000 based on the hydraulic diameter and bulk velocity of the duct. Experiments are also performed without the duct, with the specimen exposed to approximately uniform flow at the flow conditioner exit. The Darcy-Forchheimer model is used as the basis for data analyses with consideration to nonlinear inertial effects at high Re. The exact point when inertial effects are larger than viscous effects depends on the porosity of the design. Experimental data are analyzed for various designs with high (∼ 0.85), medium (∼ 0.50), and low (∼ 0.15) projected area porosities and compared with select Direct Numerical Simulation (DNS) data. Non-dimensional data are analyzed using two methods, 1) a single projected zone and 2) a zonal weighting approach based on the various flow blockage regions. The data are used to investigate scaling laws that may be useful for APM designs in future passive flow control applications.