Glossary of Karst and Cave Terms

Peclet number

1. measure of the relative contribution of mechanical dispersion and diffusion to solute transport. It relates the effectiveness of mass transport by advection to the ??????????????vx D C x P C x e ????????????effectiveness of mass transport by either dispersion or diffusion . Peclet P C x e ??????????????????2 2 numbers below .0.4 indicate diffusion/dispersion control; 0.4-6.0 suggest that diffusion/dispersion and advection are in transition and thus approximately equal to each other; and >6.0 indicate advection control. Large Peclet numbers indicate strongly advective systems. 2. A relationship between the advective and diffusive components of solute transport expressed as the ratio of the product of the average interstitial velocity, times the characteristic length, divided by the coefficient of molecular diffusion. Small values indicate diffusion dominance, large values indicate advection dominance [22].