Viscosity(μ)and Non-Newtonian Flow

Viscosity(μ)and Non-Newtonian Flow

1. Viscosity is a fluid property that characterizes resistance to flow.

   • τ=μ*dV/dy

2. Viscosity(μ)= shear stress/ rate of shear strain=τ/ (dv/dy)

   • Viscosity cause a force called shear force, analogous to frictional forces.
   • shear stress is the ratio of tangential force to area at a point on a surface.
     • τ=F/A
   • Rate of shear strain is the change in an angle of a particle as a function of time.
     • rate of shear strain =Φ / t

3. Viscosity of gas incereases with temperature rise and viscosity of liquid decreases.

4. Shear stress is not directly proportional to the rate of strain called non-Newtonian fluid.

   • Examples: cream, honey, tomato sauce

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