Non-newtonian fluids

Definition

Non-newtonian fluids are substances whose viscosity changes when under stress or shear rate, unlike Newtonian fluids which maintain a constant viscosity regardless of the applied forces. This unique behavior means that non-newtonian fluids can exhibit properties such as thickening or thinning depending on how quickly or slowly they are stirred, making them essential in various applications, from industrial processes to everyday products like paints and food items.

5 Must Know Facts For Your Next Test

1. Non-newtonian fluids can be categorized into different types based on their behavior under stress, including shear-thinning (pseudoplastic), shear-thickening (dilatant), Bingham plastics, and viscoelastic fluids.
2. Common examples of non-newtonian fluids include ketchup, which becomes less viscous when shaken, and cornstarch mixed with water, which behaves as a solid under sudden force but flows easily when moved slowly.
3. The study of non-newtonian fluids is crucial in industries such as food processing, cosmetics, and pharmaceuticals, where the flow properties can significantly affect production processes.
4. Understanding non-newtonian behavior is important for predicting how these fluids will behave in real-world applications, such as in pipelines or during mixing and processing.
5. Non-newtonian fluids can also display complex behaviors like time-dependent viscosity changes, making their mathematical modeling challenging compared to simple Newtonian fluids.

Review Questions

• How do non-newtonian fluids differ from Newtonian fluids in terms of viscosity and flow behavior?
  • Non-newtonian fluids differ from Newtonian fluids primarily in their response to applied stress or shear rates. While Newtonian fluids maintain a constant viscosity regardless of the forces acting on them, non-newtonian fluids exhibit varying viscosity depending on the stress they experience. This means that under certain conditions, non-newtonian fluids can become thicker or thinner, leading to complex flow behaviors that are not observed in Newtonian fluids.
• What are the implications of non-newtonian fluid behavior in industrial applications such as food processing and paint manufacturing?
  • The behavior of non-newtonian fluids has significant implications for industrial applications because their viscosity can change during processing and use. In food processing, understanding how ingredients like sauces or dough behave under different shear conditions can improve mixing and texture. In paint manufacturing, controlling the flow properties of paint ensures proper application and finish. Thus, recognizing and predicting non-newtonian fluid behavior is critical for optimizing production efficiency and product quality.
• Evaluate how the study of non-newtonian fluids contributes to advancements in material science and engineering.
  • The study of non-newtonian fluids plays a vital role in advancements in material science and engineering by providing insights into the complex interactions between molecular structures and flow behavior. Understanding these fluids helps engineers design better materials with tailored properties for specific applications, such as flexible electronics or smart materials that respond dynamically to external stimuli. Moreover, research into non-newtonian behaviors fosters innovations in creating sustainable materials by optimizing formulations that enhance performance while minimizing waste.

Related terms

Viscosity: A measure of a fluid's resistance to flow, indicating how thick or thin it is.

Shear Stress: The force per unit area applied parallel to the surface of a material, influencing the flow behavior of fluids.

Thixotropy: A property of certain non-newtonian fluids that become less viscous when agitated or shaken and return to a more viscous state when left undisturbed.