Non-Newtonian Fluids and Viscoelasticity — Lesson 3

This lesson covers the intricate details of Non-Newtonian fluids and their viscoelastic behavior. It begins with a recap of the characteristics of Newtonian fluids and how they serve as a base to define Non-Newtonian fluids. The lesson then delves into the classification of Non-Newtonian fluids into time-independent, time-dependent, and viscoelastic categories. The lesson discusses the properties of these categories, with a focus on time-dependent Non-Newtonian fluids and viscoelastic Non-Newtonian fluids. The lesson also includes practical examples and problems related to these fluid types, such as the behavior of a body lotion and cement paste. The lesson concludes with an explanation of the concept of normal stress in steady shearing flow and the importance of this concept in understanding viscoelastic behavior.

Video Highlights

00:48 - Discussion on the characteristics of Newtonian fluids and non-Newtonian fluids.
33:25 - Explanation of the concept of thixotropy and rheopexy in time dependent non-Newtonian fluids.
43:57 - Explanation of the concept of viscoelastic fluids and their examples.
56:00 - Discussion on the concept of normal stress in steady shearing flow and the importance of normal stress coefficients in viscoelastic fluids.
62:42 - Explanation of the concept of recoverable shear and its importance in determining the degree of elastic behavior of a liquid.

Key Takeaways

• Non-Newtonian fluids are classified into time-independent, time-dependent, and viscoelastic categories based on their characteristics.
• Time-dependent Non-Newtonian fluids and viscoelastic Non-Newtonian fluids exhibit unique behaviors due to their dependence on the duration of shearing.
• The concept of normal stress in steady shearing flow is crucial in understanding the viscoelastic behavior of Non-Newtonian fluids.
• Practical examples, such as the behavior of body lotion and cement paste, help in understanding the real-world applications of these fluid types.