# Dynamic Viscosity

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## Dynamic Viscosity

Dynamic viscosity ( $$\mu$$ ) (also called absolute viscosity of simple viscosity) is the force required to move adjacent layers that are parallel to each other at different speeds.  The velocity and shear stress are combined to determine the dynamic viscosity.

### Dynamic Viscosity Formula

$$\mu = \frac {\tau} {\dot {\gamma}}$$          $$dynamic \; viscosity \;=\; \frac { shear \; stress } { shear \; rate }$$

Where:

$$\mu$$ (Greek symbol mu) = dynamic viscosity

$$\tau$$ (Greek symbol tau) = shear stress

$$\dot {\gamma}$$ (Greek symbol gamma) = shear rate