Definition of Pseudoplastic Flow (Shear-Thinning):
- Pseudoplastic Flow (Shear-Thinning) shows viscosity decreases with rising shear rate in fluids.
- Pseudoplastic fluids decrease in viscosity with increasing shear rate.
- The more you stir or apply shear, the thinner the fluid becomes.
Here’s the graph showing the shear-thinning behavior of a pseudoplastic fluid. As shear rate increases, the shear stress increases at a decreasing rate, indicating reduced viscosity.
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Rheological Behavior:
- No yield stress
- Shear-thinning
- Flow curve is concave downward (shear stress vs. shear rate)
Equation (Power Law):
$\tau = K \cdot \dot{\gamma}^n \quad \text{where } n < 1$
- Where:
- K: consistency index
- n: flow behavior index (<1 for pseudoplastics)
Examples:
- Methylcellulose or CMC solutions
- Emulsions
- Ketchup
- Topical gels
