ABSTRACT
Rheology is a subject which addresses the deformation of fluids. A constitutive equation defines the cause and effect relationships in terms of the properties or characteristics of the fluid material. To develop such relationships balance equations must be derived. A balance equation is merely a mathematical statement of the universal laws of conservation of mass, energy, and momentum that are specific to the system of interest. Time-dependent non-Newtonian fluids can exhibit the property of a yield stress. The Bingham plastic fluid itself is idealistic, it can be applied to modeling a portion of a real non-Newtonian’s flow curve. The flow curves are constructed from data generated by a single experiment in which the shear rate is steadily increased from zero to some maximum value and then immediately decreased toward zero. The arrows on the curves denote the chronological progress of the experiment.
