In such a fluid application, dynamic viscosity should be measured. For such fluids, determining the internal resistance is important to calculate the force required to move the fluid. When a fluid changes its characteristics upon the application of force or pressure, it is a non-Newtonian fluid. The table below compares the dynamic viscosity and kinematic viscosity of liquid water from 0℃ to its normal boiling point.Ĭhoosing the Proper Measurement Dynamic Viscosity The viscosity of liquid water decreases with an increase in temperature. There are several engineering properties for water, including thermal expansion, isothermal compression, thermal conductivity, specific heat, specific entropy, specific enthalpy, saturation vapor pressure, dynamic viscosity, and kinematic viscosity. The Dynamic and Kinematic Viscosity of Water The table above compares the properties of dynamic viscosity vs.

However, there is no way that the kinematic viscosity of two different fluids can be the same due to the differences in their density. The dynamic viscosity of two different fluids can be the same. The kinematic viscosity gives the inherent resistance of the fluid to flow when there is no external force applied to it except gravity. When the resistance to flow is measured under the weight of gravity, then the viscosity is called kinematic viscosity. The dynamic viscosity measures the resistance offered by the fluid to the flow when an external force is applied.

The dynamic viscosity divided by the density of the fluid gives kinematic viscosity. The absolute or dynamic viscosity is the ratio of shear stress to shear strain. In this article, we will compare the dynamic vs. kinematic viscosity, it is important to note that no two fluids can have the same kinematic viscosity, but they can have the same dynamic viscosity. The viscosity of fluids can be expressed in terms of either dynamic viscosity or kinematic viscosity. Fluids differ in the internal resistance that is exerted, causing differences in viscosity as well. In fluids, the resistance to flow or to deform is known as viscosity. In fluids, the resistance to flow or to deform is known as viscosity Whenever a fluid is not subjected to physical forces other than gravitational force, kinematic viscosity is the right measurement. When external forces are applied to a fluid, dynamic viscosity measurements are the best choice. The conversion of conventional measures into cSt is inaccurate, particularly within the 1 to 9.5 cSt range (see DIN 1342, viscosity of NEWTONian liquids).No two fluids can have the same kinematic viscosity, but they can have the same dynamic viscosity. If values higher than 1000 cSt are required, the data given from 60 cSt can be multiplied accordingly by 10, 100, 1000 etc. The table can also alternatively be used to assign corresponding values to one another. The former units are no longer approved and can be converted to m²/s using Fig. To ensure correct usage, the Stokes units and the units still currently in general use must be converted into the SI unit m 2/s. These are: degrees Engler (✮) in Germany, Saybolt seconds (S˝) in USA and Redwood seconds (R˝) in Britain. The conventional units of viscosity are unsuitable as a basis for calculation, but are still used in commerce. The Stokes unit ceased to be officially valid in 1978. The hundredth part thereof is a Centi stokes (cSt). The unit used here is m 2/s and is called – in honour of the Irish physicist STOKES – a Stokes (St). However, most measurements are still made in centistokes, e.g. Thus water at 20 ✬ has a kinematic viscosity ν = 1,002 Kinematic viscosity (ν) designates the quotient of the dynamic viscosity of the fluid handled and its density.

Kinematic viscosity of water at 10 c