# Kinematic Viscosity

on . Posted in Classical Mechanics

Kinematic viscosity, abbreviated as $$\nu$$ (Greek symbol nu), is a fluid property that describes its resistance to flow under the influence of gravity.  It is a measure of the fluid's internal friction and represents the ratio of dynamic viscosity to density.  The kinematic viscosity provides a measure of how easily a fluid can flow or be deformed under the influence of gravity.  It is an important property in fluid dynamics, particularly in the study of laminar and turbulent flows, fluid behavior in pipes, and the calculation of flow rates and pressure losses in various engineering applications.

### Kinematic Viscosity Index

The kinematic viscosity of a fluid depends on factors such as temperature, pressure, and the nature of the fluid itself.  As temperature increases, kinematic viscosity tends to decrease for most fluids.  Different fluids have different inherent viscosity characteristics, which can impact their flow behavior and application suitability.

Kinematic viscosity is commonly used in the calculation of Reynolds number, which is a dimensionless quantity that characterizes the flow regime (laminar or turbulent) of a fluid.  It is also a key parameter in the design and analysis of fluid systems, lubrication, hydraulic applications, and the selection of appropriate fluids for specific industrial processes.

### Kinematic viscosity formula

$$\nu = \mu \;/\; \rho$$     (Kinematic Viscosity)

$$\mu = \nu \;/\; \rho$$

$$\rho = \mu \;/\; \nu$$

Symbol English Metric
$$\nu$$  (Greek symbol nu) = kinematic viscosity $$ft^2 \;/\; sec$$ $$m^2 \;/\; s$$
$$\mu$$  (Greek symbol mu) = dynamic viscosity $$lbf-sec \;/\; ft^2$$ $$Pa-s$$
$$\rho$$  (Greek symbol rho) = fluid mass density $$lbm \;/\; ft^3$$ $$kg \;/\; m^3$$

### Kinematic viscosity formula

$$\nu = Pr \; \alpha$$     (Kinematic Viscosity)

$$Pr = \nu \;/\; \alpha$$

$$\alpha = \nu \;/\; Pr$$

Symbol English Metric
$$\nu$$  (Greek symbol nu) = kinematic viscosity $$ft^2 \;/\; sec$$ $$m^2 \;/\; s$$
$$Pr$$ = Prandtl number $$dimensionless$$ $$dimensionless$$
$$\alpha$$  (Greek symbol alpha) = thermal diffusivity $$ft^2 \;/\; sec$$ $$m^2 \;/\; s$$

### Kinematic viscosity formula

$$\nu = Sc \; D_m$$     (Kinematic Viscosity)

$$Sc = \nu \;/\; D_m$$

$$D_m = \nu \;/\; Sc$$

Symbol English Metric
$$\nu$$  (Greek symbol nu) = kinematic viscosity $$ft^2 \;/\; sec$$ $$m^2 \;/\; s$$
$$Sc$$ = Schmidt number $$dimensionless$$ $$dimensionless$$
$$D_m$$ = mass diffusivity $$ft^3 \;/\; sec$$ $$m^3 \;/\; s$$

Tags: Viscosity