Stokes-Einstein equation


According to Stokes’ law, a perfect sphere traveling through a viscous liquid feels a drag force proportional to the frictional coefficient. The diffusion coefficient D of a sherical particle istproportional to its mobility: Substituting the frictional coefficient of a perfect sphere from Stokes’ law by liquid’s viscosity and sphere’s radius we have Stokes-Einstein equation.

Related formulas


DDiffusion coefficient (m2/s)
kBBoltzmann constant
TThe temperature (K)
n The dynamic viscosity (Pa*s)
rThe radius of the spherical practicle (m)