# Is viscosity time dependent?

## Is viscosity time dependent?

The viscosity of the fluid is dependent on temperature, shear rate and time. Depending on how viscosity changes with time the flow behaviour is characterised as: thixotropic (time thinning, i.e. viscosity decreases with time) rheopectic (time thickening, i.e. viscosity increases with time)

Which viscosity is ETA?

The dynamic viscosity η (η = “eta”) is a measure of the viscosity of a fluid (fluid: liquid, flowing substance). The higher the viscosity, the thicker (less liquid) the fluid; the lower the viscosity, the thinner (more liquid) it is.

How is viscosity related to time?

Some non-Newtonian pseudoplastic fluids show a time-dependent change in viscosity and a non-linear stress-strain behavior in which the longer the fluid undergoes shear stress, the lower its viscosity becomes. When stress ceases, they regress to their more viscous state after a passage of time.

### Is rheopectic time dependent?

Rheopecty or rheopexy is the rare property of some non-Newtonian fluids to show a time-dependent increase in viscosity (time-dependent viscosity); the longer the fluid undergoes shearing force, the higher its viscosity. Rheopectic fluids, such as some lubricants, thicken or solidify when shaken.

What is time dependent and time independent fluid?

Non-Newtonian fluids, time dependent. The viscosity of the fluid is dependent on temperature, shear rate and time. Depending on how viscosity changes with time the flow behaviour is characterised as: thixotropic (time thinning, i.e. viscosity decreases with time) Time independent fluids.

What is MU in fluids?

μ (mu) is the dynamic viscosity of the fluid (Pa·s = N·s/m2 = kg/(m·s)), ν (nu) is the kinematic viscosity (ν = μρ) (m2/s), ρ (rho) is the density of the fluid (kg/m3), W is the mass flowrate of the fluid (kg/s).

#### What is time dependent fluid?

Time dependent fluids are fluids whose viscosity de- pends on the duration of flow, The well known thixotropic fluids form a part of this category, because they become runny on being stirred and gel on being left.

What is the relationship of viscosity and time of flow?

The resistance to flow in turn is directly proportional to the viscosity η . Thus, the flow rate is inversely proportional to the viscosity.