If D is the fluid dispersion coefficient, L is the length of spread of tracer and u is the fluid velocity, then which of the following represents Dispersion number?

If D is the fluid dispersion coefficient, L is the length of spread of

1.	If D is the fluid dispersion coefficient, L is the length of spread of tracer and u is the fluid velocity, then which of the following represents Dispersion number?
A.	( frac{L}{uD} )
B.	( frac{L}{D} )
C.	( frac{D}{uL} )
D.	( frac{Lu}{D} )
Answer» D. ( frac{Lu}{D} )