Couette viscometer When a liquid is sheared the lubricant exerts a resisting shear stress $\tau$ to the motion. The proportion between resistance and certain shear rate $\dot{\gamma}}=\frac{\partial u}{\partial y}$ may be called viscosity $\mu$. By using the definition \begin{equation}\label{eq:mu}\tau=\mu\cdot \frac{\partial u}{\partial y}\end{equation} the viscosity can be derived from measurements. A steady shear experiment with a… Continue reading Viscosity measurement