Dynamic vs. kinematic viscosity are types of viscosity. Viscosity helps represent the fluidity and thickness of a product. Viscosity is an important property of a liquid when analyzing the behavior of the liquid or the movement of the liquid near the boundary of the solid.
Viscosity is an important property of a liquid when analyzing the behavior of the liquid or the movement of the liquid near the boundary of the solid. Due to shear or tensile stress, the viscosity of a liquid is a measure of its resistance to gradual deformation. When low liquids try to slide against each other, the shear resistance of the liquids is caused by intramolecular friction.
The relationship between shear stress and shear stress is called dynamic viscosity and is generally measured in centipoise (cP), with Pa-s as the unit of measurement. The ratio of the kinematic viscosity of a liquid to its density is called the kinematic viscosity, and the unit of measurement is m2/s.
Two different liquids do not have the same kinematic viscosity due to their different densities, but they may have the same kinematic viscosity. The kinematic viscosity indicates the speed at which the liquid moves when a specific force is applied, and the kinematic viscosity provides information about the force required to make the liquid flow at a specific speed.
In SI units, the unit of kinematic viscosity is well established as mPa-s, and the most common unit of kinematic viscosity is cm2/s.
The tangential force required to move a horizontal plane from one liquid to another is called dynamic viscosity. or
A measure of a fluid's resistance to shear flow when some external force is applied is known as dynamic viscosity.
It helps explain the behavior of liquids under stress. It is also primarily used to describe non-Newtonian fluids by observing how their viscosity changes in response to changes in shear rate.
The dynamic viscosity = shearing stress/shearing rate change.
The equation is;
η = τ / γ
Where,
η is the dynamic viscosity
τ is shearing stress &
γ is a shearing rate change.
Rotational viscometers are one of the most commonly used instruments for measuring dynamic viscosities, and for fluid samples, these instruments rotate the probe. Viscosity is determined by measuring force or torque.
This viscometer can adjust the speed of rotation of the probe as it moves through the liquid, and the viscometer detects changes in the viscosity of the sample as the speed.
Examples:
The fluid used in hydraulics, lubricants to avoid friction bearings, seals, etc.
The relationship between the kinematic viscosity and the density of the liquid is called the kinematic viscosity. Also
A measure of the inherent resistance to fluid flow when no external force other than gravity is applied is known as kinematic viscosity.
The kinematic viscosity can be obtained by dividing the absolute viscosity or dynamic viscosity of a liquid by the mass density of the liquid, and Centipoise (cP) is a measurement unit of dynamic viscosity.
The kinematic viscosity = Dynamic viscosity / Fluid mass density.
The equation is;
ν = η / ρ
Where,
η is the kinematic viscosity
ρ is fluid density &
η is a dynamic viscosity.
There are several ways to determine the kinematic viscosity of a liquid, but the most common is a capillary viscometer. This method determines how long it takes for the fluid to flow through the capillaries. Time is directly converted to kinematic viscosity using the calibration constants provided for a particular tube.
Centistokes (CST) is a unit of measurement of kinematic viscosity.
Examples:
The fluids flowing in pipes and everything which involves more movement from one point to another are examples of kinematic viscosity.