3. Terminology
3.1 Definitions
3.1.1 Newtonian oil or fluid, n-one that exhibits a constant viscosity at all shear rates.
3.1.2 non-Newtonian oil or fluid, n-one that exhibits a viscosity that varies with changing shear stress or shear rate.
3.1.3 viscosity, , n-the property of a fluid that determines its internal resistance to flow under stress, expressed by:
3.1.3.1 Discussion - It is sometimes called the coefficient of dynamic viscosity. This coefficient is thus a measure of the resistance to flow of the liquid. In the SI, the unit of viscosity is the pascal-second; for practical use, a submultiple (millipascal-second) is more convenient and is customarily used. The millipascal second is 1 cP.
3.2 Definitions of Terms Specific to This Standard
3.2.1 apparent viscosity, n-the viscosity obtained by use of this test method.
3.2.1.1 Discussion - Since many engine oils are non-Newtonian at low temperature, apparent viscosity can vary with shear rate.
3.2.2 calibration oils, n-oils with known viscosity and viscosity/temperature functionality that are used to define the calibration relationship between viscosity and cold-cranking simulator rotor speed.
3.2.3 test oil, n-any oil for which the apparent viscosity is to be determined by use of this test method.
3.2.4 viscoelastic oil, n-a non-Newtonian oil or fluid that climbs up the rotor shaft during rotation.
