Handbook of Physical Constants

Contents | ||
Page | ||
Table 10 | 1. Viscosity of certain mineral and rock glasses | 133 |
2. Viscosity in the system orthoclase-albite | 136 | |
3. Viscosity in the system diopside-albite-anorthite | 136 | |
4. Viscosity computed from field measurements | 136 | |
5. Effect of pressure upon viscosity | 137 |
Contents | ||
Page | ||
Table 10 | 1. Viscosity of certain mineral and rock glasses | 133 |
2. Viscosity in the system orthoclase-albite | 136 | |
3. Viscosity in the system diopside-albite-anorthite | 136 | |
4. Viscosity computed from field measurements | 136 | |
5. Effect of pressure upon viscosity | 137 |
According to Newton’s law of fluid friction, the tangential or shearing stress in a liquid in motion is proportional to the rate of change, with time, of the angle of shear. Real liquids may be divided into two categories: “Newtonian” or “viscous” liquids, for which the factor of proportionality, the “viscosity,” is independent of the “rate of shear”; and “non-Newtonian” liquids, for which the factor depends upon this rate. The “Newtonian” behavior of many ordinary liquids, and of some glasses, has been verified for considerable ranges of shear rate. “Non-Newtonian” behavior has been observed for such materials as certain colloidal solutions, asphalt, and other bituminous products; no single value of “viscosity” is sufficient to describe the flow of such materials. (See also Section 9.) If the stress is measured in dynes × cm.−2, and the rate of shear in radians × sec.−1, the viscosity will be given in dyne × sec. × cm.−2 or the equivalent unit, gram × sec.−1 × cm. −1 This unit is called the poise and is used in the tables in this section.
The viscosity of a given material depends upon the pressure and temperature. Other factors of great importance for geological applications remain to be investigated, such as the effect of dissolved gases . . .