Pair stress approximation

Pair stress approximation for hard particles is given by (Eq. 3.18)

$\rho B_{2}={\frac {q}{(1+q)^{B_{3}}}}$

where $q=P/k_{B}T\rho -1$, $B_{2}$ is the second virial coefficient and $B_{3}$ is the third virial coefficient.

See also

• Scaled-particle theory
• BBGKY hierarchy