Finite Element Techniques for Fluid Flow

DISPERSION PROBLEMS

259

diffusing through a liquid of total density p (density of component 1

plus 2, i.e.

p

= Pi + p

2

)\ the value of K

m

depends on many para-

meters. In formula (8.1) the diffusion is assumed to be isotropic, i.e.

equal in all directions. A more general expression for the components

of

q

is

qj= -pKTj

The quantity

p

x

jp

will be called 0, the concentration of component

1 in the 'host' fluid. Thus (8.2) becomes

*=-HI)

(83)

The mixing processes in fluids are very much affected by turbu-

lence

;

i.e. the velocities at a point are random in such a fashion that

the fluid can be visualised as having an average velocity plus some

standar ...