Kinematic Viscosity to Dynamic Viscosity Calculator

This Kinematic Viscosity to Dynamic Viscosity Calculator is a powerful tool used to convert between two essential fluid properties: kinematic viscosity and dynamic viscosity.

You have a fluid with a kinematic viscosity of 100 mm²/s (square millimeters per second) and a density of 0.8 g/cm³. The calculator tells that the dynamic viscosity of this fluid is 80 mPa·s (millipascal-seconds). This conversion allows scientists and engineers to work with the most appropriate viscosity measure for their specific applications.

Kinematic Viscosity to Dynamic Viscosity Conversion Chart

• 20 mm²/s with a density of 1.0 g/cm³ provides a straightforward conversion, yielding a dynamic viscosity of 20 mPa·s.
• 30 mm²/s with a density of 0.95 g/cm³ results in a dynamic viscosity of 28.5 mPa·s, illustrating how slight changes in density can affect viscosity.
• 75 mm²/s with a density of 0.85 g/cm³ results in a dynamic viscosity of 63.75 mPa·s, showcasing a more viscous fluid.
• Higher values such as 150 mm²/s and 200 mm²/s with their respective densities demonstrate the increasing trend in dynamic viscosity as kinematic viscosity increases.

Kinematic Viscosity to Dynamic Viscosity Formula

The formula for converting kinematic viscosity to dynamic viscosity is:

Dynamic Viscosity (μ) = Kinematic Viscosity (ν) * Density (ρ)

Where:

• Dynamic Viscosity (μ) is typically measured in Pa·s (pascal-seconds) or mPa·s
• Kinematic Viscosity (ν) is often measured in mm²/s or cSt (centistokes)
• Density (ρ) is usually measured in g/cm³ or kg/m³

To convert a kinematic viscosity of 75 mm²/s for a fluid with a density of 0.95 g/cm³:

Dynamic Viscosity = 75 mm²/s 0.95 g/cm³
= *71.25 mPa·s

This calculation shows that the fluid has a dynamic viscosity of 71.25 mPa·s.

How do you convert kinematic viscosity to dynamic viscosity?

Let’s use a practical example:

Suppose you’re working with a lubricating oil that has a kinematic viscosity of 40 cSt (centistokes, equivalent to mm²/s) at 40°C, and its density is 0.88 g/cm³.

Using our formula:

Dynamic Viscosity = Kinematic Viscosity Density
= 40 mm²/s 0.88 g/cm³
= 35.2 mPa·s

This result tells us that the lubricating oil has a dynamic viscosity of 35.2 mPa·s at 40°C. This information is valuable for understanding how the oil will perform under specific conditions and for comparing it to other lubricants.

What is dynamic viscosity and kinematic viscosity?

Dynamic viscosity, also known as absolute viscosity, is a measure of a fluid’s internal resistance to flow under an applied force. It quantifies the fluid’s “thickness” or resistance to shearing flows, where adjacent layers move at different velocities. Dynamic viscosity is typically measured in pascal-seconds (Pa·s) or poise (P).

Kinematic viscosity, on the other hand, is the ratio of dynamic viscosity to density. It represents the fluid’s resistance to flow under the influence of gravity. Kinematic viscosity is commonly measured in square meters per second (m²/s) or stokes (St).

The key difference between these two properties lies in their consideration of the fluid’s density. Dynamic viscosity is an intrinsic property of the fluid, while kinematic viscosity takes into account both the fluid’s resistance to flow and its density.

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