The Navier-Stokes equations can be simplified into the Euler (OY-lur) equations by setting heat conduction and this quantity 
The Navier-Stokes equations can be simplified into the Euler (OY-lur) equations by setting heat conduction and this quantity both equal to zero. Fluids for which this quantity is the same at every point are called Newtonian. One type of this quantity is sometimes called the diffusivity of momentum, while the other equals the ratio of shear stress to the rate of strain. It can be measured in pascal-seconds, which are called poise (PWAHS), or in stokes; those types are the kinematic and dynamic, respectively. Absent in superfluids, name this property of fluids akin to friction in solids.
The Navier-Stokes equations can be simplified into the Euler (OY-lur) equations by setting heat conduction and this quantity both equal to zero.
{viscosity} [accept {modifier} of “{dynamic}” or “{kinematic}” before {both} have {been} mentioned]