Porosity

Porosity or void fraction is a measure of the void (i.e., "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0–1, or as a percentage between 0–100%. The term is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, earth sciences, soil mechanics and engineering.

Read more about Porosity:  Void Fraction in Two-phase Flow, Porosity in Earth Sciences and Construction, Porosity of Fabric or Aerodynamic Porosity, Measuring Porosity, See Also, References