Type II fluids are described as which flow behavior?

Type II fluids are described as which flow behavior?

• A. Newtonian
• B. Pseudoplastic
• C. Dilatant
• D. Bingham plastic

Answer: (B)

Non-Newtonian fluids can change their viscosity depending on how hard you push on them. Type II de-icing fluids behave as shear-thinning, or pseudoplastic, materials: their viscosity drops as the shear rate increases. This is exactly what’s needed in practice—when the fluid sits on a surface, it stays relatively viscous to cling and form a protective film; when it’s pumped through a nozzle or sprayed, the higher shear lowers the viscosity so it flows more easily and coats evenly. The other flow descriptions don’t fit: Newtonian fluids keep the same thickness regardless of shear, dilatant fluids get thicker with more shear, and Bingham plastics act like a solid until a yield stress is exceeded and then flow with a constant viscosity. So the correct description is pseudoplastic.

Non-Newtonian fluids can change their viscosity depending on how hard you push on them. Type II de-icing fluids behave as shear-thinning, or pseudoplastic, materials: their viscosity drops as the shear rate increases. This is exactly what’s needed in practice—when the fluid sits on a surface, it stays relatively viscous to cling and form a protective film; when it’s pumped through a nozzle or sprayed, the higher shear lowers the viscosity so it flows more easily and coats evenly. The other flow descriptions don’t fit: Newtonian fluids keep the same thickness regardless of shear, dilatant fluids get thicker with more shear, and Bingham plastics act like a solid until a yield stress is exceeded and then flow with a constant viscosity. So the correct description is pseudoplastic.