Depending on the design, they are appropriate for both Newtonian and non-Newtonian products like syrups, sauces and yogurt. A rotating cylinder, or other circular geometric configuration creates a defined shear rate in the sample and measures resistance to flow by the torque generated. They produce precise measurements of absolute viscosity for a wide range of viscosities. Because the shear rate can be varied, it is possible to plot the flow curves of non-Newtonian fluids. Time effects can be studied either manually or automatically with computerized controls.
Computer programs are able to conduct advanced or specialized viscosity analyses.
This second type is subdivided, based on whether the inner or outer cylinder rotates to produce flow. Searle types have an inner cylinder, called a rotor or bob, rotating to produce flow while the outer cylinder remains fixed. A sensing unit positioned between the drive motor and the shaft connected to the inner cylinder measures torque. According to Richards, the advantage of this system is that the temperature can be more precisely controlled via a jacket on the outer cylinder. The Courette type has an outer cylinder or cup that rotates at a defined speed.