a law giving the force of resistance F experienced by a sphere when it undergoes slow translational motion in an unbounded viscous fluid. The law states that F = 6πμrv, where μ, is the viscosity of the fluid, r is the radius of the sphere, and v is the speed of the sphere. This formula was set forth by G. G. Stokes in 1851. The law holds only for small Reynolds numbers Re « 1.
Stokes’ law has applications in colloid chemistry, molecular physics, and meteorology. The law can be used to determine the settling speed of fine fog droplets, colloid particles, silt particles, or other small particles. The terminal velocity vter of a small sphere falling through a viscous fluid is
where ρ is the density of the fluid, ρ’ is the density of the sphere, and g is the acceleration of gravity. Stokes’ law is used in viscosi-metry to determine the viscosity of very viscous fluids.
REFERENCE
Loitsianskii, L. G. Mekhanika zhidkosti i gaza, 3rd ed. Moscow, 1970. Subsection 92.Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content.
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