Search results
Results from the WOW.Com Content Network
Increasing temperature results in a decrease in viscosity because a larger temperature means particles have greater thermal energy and are more easily able to overcome the attractive forces binding them together. An everyday example of this viscosity decrease is cooking oil moving more fluidly in a hot frying pan than in a cold one.
Shear thinning in a polymeric system: dependence of apparent viscosity on shear rate. η 0 is the zero shear rate viscosity and η ∞ is the infinite shear viscosity plateau. At both sufficiently high and very low shear rates, viscosity of a polymer system is independent of the shear rate.
In addition, viscosity tends to increase with temperature in gases and decrease with temperature in liquids. Above the liquid-gas critical point , the liquid and gas phases are replaced by a single supercritical phase .
In physics and chemistry, a non-Newtonian fluid is a fluid that does not follow Newton's law of viscosity, that is, it has variable viscosity dependent on stress. In particular, the viscosity of non-Newtonian fluids can change when subjected to force. Ketchup, for example, becomes runnier when shaken and is thus a non-Newtonian fluid.
MÄnuka honey is an example of a thixotropic material.. Thixotropy is a time-dependent shear thinning property. Certain gels or fluids that are thick or viscous under static conditions will flow (become thinner, less viscous) over time when shaken, agitated, shear-stressed, or otherwise stressed (time-dependent viscosity).
In continuum mechanics, time-dependent viscosity is a property of fluids whose viscosity changes as a function of time. The most common type of this is thixotropy , in which the viscosity of fluids under continuous shear decreases with time; the opposite is rheopecty , in which viscosity increases with time.
Plotting this, one finds that the longest wavelengths are the most unstable. As importantly, one can note that the viscosity of the fluid thread does not influence which wavelengths will be stable. Viscosity only acts to decrease how rapidly a given perturbation will grow or decay with time.
The viscosity of an aqueous solution can either increase or decrease with concentration depending on the solute and the range of concentration. For instance, the table below shows that viscosity increases monotonically with concentration for sodium chloride and calcium chloride , but decreases for potassium iodide and cesium chloride (the ...