Viscosity of Amorphous Materials

Viscosity Of Amorphous Materials

The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the informal notion of "thickness". For example, honey has a higher viscosity than water.

Viscosity is due to friction between neighboring parcels of the fluid that are moving at different velocities. When fluid is forced through a tube, the fluid generally moves faster near the axis and very little near the walls, therefore some stress (such as a pressure difference between the two ends of the tube) is needed to overcome the friction between layers and keep the fluid moving. For the same velocity pattern, the stress is proportional to the fluid's viscosity. A liquid's viscosity also depends on the size and shape of its particles and the attractions between the particles.

A fluid that has no resistance to shear stress is known as an ideal fluid or inviscid fluid. In the real world, zero viscosity is observed only at very low temperatures, in superfluids. Otherwise all fluids have positive viscosity. If the viscosity is very high, such as in pitch, the fluid will seem to be a solid in the short term. In common usage, a liquid whose viscosity is less than that of water is known as a mobile liquid, while a substance with a viscosity substantially greater than water is simply called a viscous liquid.

Read more about Viscosity Of Amorphous Materials:  Etymology, Newtonian and Non-Newtonian Fluids, Viscosity in Solids, Viscosity Measurement, Molecular Origins, Viscosity of Slurry, Viscosity of Amorphous Materials, Eddy Viscosity, See Also

Famous quotes containing the words amorphous and/or materials:

    I feel like a white granular mass of amorphous crystals—my formula appears to be isomeric with Spasmotoxin. My aurochloride precipitates into beautiful prismatic needles. My Platinochloride develops octohedron crystals,—with a fine blue florescence. My physiological action is not indifferent. One millionth of a grain injected under the skin of a frog produced instantaneous death accompanied by an orange blossom odor.
    Lafcadio Hearn (1850–1904)

    If our entertainment culture seems debased and unsatisfying, the hope is that our children will create something of greater worth. But it is as if we expect them to create out of nothing, like God, for the encouragement of creativity is in the popular mind, opposed to instruction. There is little sense that creativity must grow out of tradition, even when it is critical of that tradition, and children are scarcely being given the materials on which their creativity could work
    C. John Sommerville (20th century)