Lesson 1.2c Definition of Viscosity
Goals You can:
- Explain the meaning of stress, shear stress, normal stress, rate-of-shear-strain, velocity gradient
- Explain the meaning of a Newtonian Fluid and a Non-Newtonian Fluid. Give examples of fluids in each of these categories.
- Relate shear stress and velocity gradient using the definition of viscosity (Eq. 1)
\begin{align} \tau =\mu \frac{dV}{dy} \end{align}
Rationale
- Shear stress (i.e. viscous stress) causes head loss, pressure drop, drag, energy loss etc. It is of paramount importance in many practical applications.
Resouces
- Text section 2.4
- Non-newtonian on wikipedia
- Shear thickening fluid on a speaker--youtube