ABSTRACT

Substituting u 5 0 into Equation 3.15 from 2.3 gives the equation of particle motion in a quiescent fluid:

d dt

C D

gν ν ρ ρ

ρ ρ ρ

52  23

( )

(4.1)

When the first term (the hydrodynamic resistance force) on the right-hand side of Equation 3.15 from 2.3 is counterbalanced by the second term (the hydrodynamic resistance force), the spherical particle settling under the gravity attains a uniform velocity. It is called the terminal settling velocity.