Viscosity
Hydraulic fluids - Analysis methods

Dynamic viscosity [23][29] is measured using coaxial cylinder viscometers (figure 2). The prototype was the Couette viscometer. The gap between the two cylinders is filled with fluid. One of the cylinders is set in motion. The other is stationary. The test temperature is regulated to the desired value.

Measurements are carried out by applying a constant torques $\mathcal{C}$ and determining the viscous frictional torque M of the oil sample occupying the annular space between rotor and stator. The device constant...