3. Conclusion

This article presents various techniques for measuring viscosity. The term "viscosity" covers much more than the simple coefficient of viscosity derived from Newton's law. The notions of shear viscosity, elongational viscosity and complex viscosity were defined in the previous article [R 2 350] . Moreover, characterizing the behavior of a liquid or pasty material in flow is not limited to knowledge of a viscosity coefficient alone, since it also depends – among other things – on the material's elasticity.

By its very definition, viscosity measurement requires that flow conditions...