Equivalent spherical diameter
According to the IUPAC definition, the equivalent diameter of a non-spherical particle is equal to a diameter of a spherical particle that exhibits identical property (e.g., aerodynamic, hydrodynamic, optical, electrical) to that of the investigated non-spherical particle. For particles in non-turbulent motion, the equivalent diameter is identical to the diameter encountered in the Stokes' law.
- Jennings, B. R. and Parslow, K. (1988) Particle Size Measurement: The Equivalent Spherical Diameter. Proceedings of the Royal Society of London. Series A 419, 137-149
- Definition of equivalent diameter in the IUPAC goldbook