What is the difference between relative and absolute viscosity?
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What is the difference between relative and absolute viscosity?
Absolute or dynamic viscosity is the internal resistance that a fluid faces against flowing freely. Relative viscosity is the ratio of viscosity of a solution containing a solute to the viscosity of the pure solvent.
What do you mean by dynamic viscosity?
Dynamic viscosity is the force needed by a fluid to overcome its own internal molecular friction so that the fluid will flow. Dynamic viscosity is also referred as absolute viscosity in the field of fluid mechanics.
What is viscosity measured by?
The viscosity of a liquid (see Viscosity) is measured using a viscometer, and the best viscometers are those which are able to create and control simple flow fields.
Is viscosity same as relative viscosity?
Relative viscosity is self-explanatory. Specific viscosity expresses the incremental viscosity due to the presence of the polymer in the solution. [η] will be shown to be a unique function of molecular weight (for a given polymer-solvent pair) and measurements of [η] can be used to measure molecular weight.
How do you calculate relative viscosity?
Dividing the viscosity of the polymer solution (η) by the viscosity of the pure solvent (ηο) gives the relative viscosity with the dimensionless unit. Equation 7: Relative viscosity is the viscosity of the polymer solution divided by the viscosity of pure solvent.
How do you find absolute viscosity?
Equation (1) is known as the Newtons Law of Friction. Water at 20.2oC (68.4oF) has the absolute viscosity of one – 1 – centiPoise….Dynamic (absolute) Viscosity.
| Liquid | Absolute Viscosity *) (N s/m2, Pa s) |
|---|---|
| Glass | 1040 |
What is dynamic viscosity and its units?
Dynamic viscosity: The SI physical unit of dynamic viscosity (μ) is the Pascal-second (Pa s), which is identical to 1 kg m−1 s−1. The physical unit for dynamic viscosity in the centimeter gram second system of units (cgs) is the poise (P), named after Jean Poiseuille.
How does a viscometer measure viscosity?
Capillary viscometers Viscosity is measured by timing how long it takes for a transparent or translucent fluid to flow between two points of a capillary tube.
How is relative viscosity measured?
It can be calculated by dividing shear stress by shear rate. Relative viscosity: Relative viscosity is important for non-Newtonian fluids, specifically polymers. It’s calculated by dividing the polymer viscosity by the viscosity of the pure solvent.
What is relative viscosity?
Relative viscosity expresses the capacity of a polymer to increase the viscosity of a solution. Inherent, specific, reduced, absolute and intrinsic viscosities are all calculated using relative viscosity.
What is relative viscosity and its unit?
From Wikipedia, the free encyclopedia. Relative viscosity ( ) (a synonym of “viscosity ratio”) is the ratio of the viscosity of a solution ( ) to the viscosity of the solvent used ( ), .