Home                               Sedimentation of Spherical Particles in Liquid

  This program uses the Stokes equation to calculate the sedimentation (settling) speed of spherical particles
  The Stokes equation permits the calculation of the drag forces of a spherical particle in a viscous liquid at very low Reynolds numbers. Stoke's equation is derived from the generally not solvable Navier-Stokes equation
  Vt is the settling or terminal speed of the particle, g is the acceleration of the spherical particle, d is the diameter of the particle, pp is the density of the particle, pm the density of the liquid medium, is the dynamic viscosity of the medium. The diameter of the particle is the Stoke's diameter, which is not the actual diameter of the particle, but rather the diameter effected by absorption, hydration and deviation from the spherical shape. For non-spherical particle the Stoke's diameter can be smaller than the actual diameter. Absorption of polymers on a particle will increase the Stoke's diameter. 

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   Acceleration of gravity (g) m/s2
   Particle diameter (d) m
   Density of particle (pp) g/m3
   Density of medium (pm) g/m3
   Viscosity of medium () g.m-1.s-1


Settling Speed (Vt )

  Acheson, D. J. (1990), Elementary Fluid Dynamics, Oxford Applied Mathematics and Computing Science Series, Oxford University Press, ISBN 0198596790

Automatic recalculation 

Last edited on:

October 20, 2010

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