KURENAI : Kyoto University Research Information Repository

height from the pool surface. However, these two parameters are difficult
quantities to analyze or measure directly. Thus one needs to consider
through a more directly observable parameter. For this purpose the
interface entrainment Eo(D,jg) is introduced. E0(D,jg) represents the
entrainment consisting of droplets whose diameters are less than the
stated value D. Then it can be expressed as
E0(D,Jg)
e(J ) D
= P 9g9 J------- 0 .
ff(D,jg)dD .(25)
E0(D,jg) is an observable parameter- For example, comparing Eq. (23) and
Eq. (25) one immediately obtains that
Eo(Dc,Jg) = Efg ,(Jg) .(26)
Furthermore, the entrainment due to droplets with a diameter less
than D denoted by Efg(h,Jg,D) can be related to this parameter E 0(D,jg) as
shown -bel ow
jrE(Jg)D J jrg(vi,D,Jg)f(D,Jg)dvidD
Efg(h,Jg,D)p . (27)
9 9 o v h(D,Jg,h)
By considering the droplets with a diameter less than Dc and using the
definition of vh(D,Jg,h), one gets
vh(D,jg,h) = 0 (D < Dc)(28)
From Eqs. (21), (27) and (28), Efg(h,jg,D) can be simplified to the
following expression for D < Dc;
Ef
E ( 3 ) f
g(hgD)pJf(D,Jg)dD(29)
g g o
264