Sedimentation Theory

Sedimentation is the tendency to sedimentation of suspended particles settle to the fluid in which the driving, leaving a barrier. This is due to its motion through the fluid in response to the forces acting on them these forces can be due to gravity, electromagnetism and the centrifugal acceleration. Sedimentation is the intuition depends on the size of the particles, gravity, viscosity, etc.

Whenever you have a particle moving through a fluid flowing horizontally confined to a certain space, a number of forces come into play. The severity, type of fluid involved, since the liquid flows easily, the size of the particles, the size of the pipe or chamber, the buoyancy force, and a few smaller forces.

Sedimentation velocity is an analytical ultracentrifugation method that measures the rate at which molecules move in response to centrifugal force generated in a centrifuge. This sedimentation rate provides information about both the molecular mass and the shape of molecules. In some cases this technique can also measure diffusion coefficients and molecular mass.

In 1845 the Irish scientist George Gabriel Stokes (1819-1903) established the science of hydrodynamics with his law of viscosity, which describes the velocity of a small sphere through a viscous fluid After numerous experiments that empirically demonstrated that when a small sphere falls under gravity through a viscous medium finally acquires a constant speed.

V= 2gr²(d1-d2)/9η

V is the velocity of the particle
r is the radius of the sphere
d1 is the density of the sphere
d2 is the density of the liquid
η Is the coefficient of viscosity in poises
g is the gravitational force

In many cases, the particle motion is blocked by a hard boundary, and the resulting accumulation of particles at the boundary is called sediment. The concentration of particles at the boundary is opposed to the spread of the particles.

If you have any questions, suggestions, comments, advice, thoughts or you just want to share something with us, please email us on We would love to hear from you.