Geometric Pore size

Geometric pore size denotes the physical aperture measured directly from the medium’s structure—typically between adjacent filaments or wires—without considering tortuosity or flow distribution. It is often specified in micrometres and determined by optical or microscopic measurement. While geometric pore size gives an intuitive sense of mesh fineness, it may differ significantly from the hydraulic cut-off (mean-flow pore size or absolute rating). In woven meshes, the geometric pore corresponds to the shortest distance between crossing filaments; in nonwovens it represents an average void opening. Engineers use geometric pore size to design layered structures with predictable retention, but verify performance through porometry or particle-challenge tests that capture the real flow path distribution.