Porosity

Porosity, abbreviated as n, a dimensionless number, is the ratio between the pore volume of a substance and its total volume.  Porosity of a measure of a rocks capacity to store fluids.

 

Porosity formulas

\(\large{ n = \frac {V_v} {V_t } }\)
\(\large{ n = \frac {V_v} {V_s \;+\; V_v } }\)
\(\large{ n = \frac { e } { 1 \;+\; e } }\)
\(\large{ n = \frac { v} { v_s}  }\)	(seepage velocity)

Where:

\(\large{ n }\) = porosity

\(\large{ v }\) = Darcy velocity or flux

\(\large{ v_s }\) = seepage velocity

\(\large{ V_t } \) = total volume of soil

\(\large{ e }\) = void ratio

\(\large{ V_s }\) = volume of soil

\(\large{ V_v }\) = volume of voids (air and water)