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Non-Newtonian Fluids

Can anyone give me examples of common Non-Newtonian fluids problems? and how non-Newtonian fluids are used industry or in everyday life?

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Original post by Jammy4410

Can anyone give me examples of common Non-Newtonian fluids problems? and how non-Newtonian fluids are used industry or in everyday life?

Non-Newtonian fluids are found in spray dryers which is an industrial method to create fine powder from a liquid slurry. This fine powder can be detergent powder, coffee powder, milk powder etc.

Further applications include droplet collisions with surfaces of non-Newtonian droplets which may be important for printing with ink.

You may find, though I'm not sure, that problems involving non-Newtonian fluids involve modelling the relationship between shear stress and strain rate, by generalizing the Newtonian law accordingly. The Ostwald equation can be used in this case, where a factor of n describes "the degree of non-newtonian behavior". Flow of Non-Newtonian Fluids - Correlation of the Laminar, Transition and Turbulent Flow Regimes - Metzner and Reed, AICHE Journal, 1955.

Additionally, there is some work to find a generalised Reynolds number which works for all fluids, see Generalized Reynolds Number for Non-Newtonian Fluids - Madlener et. al, Progress in Propulsion, 2009.

Out of interest, for an interesting discussion on viscosity, see Transport Phenomena, Bird et. al, 2nd edition.. You will find that viscosity, on a molecular level, is the exchange of momentum with neighboring molecules as a molecule moves along its mean free path. The reason for the differences of viscosity with changes in temperature in liquids and gasses are to do with the different bonds associated with the two. There doesn't appear to be a simple equation for viscosity in terms of the molecules (or molecular activity) of the fluid.