For fluids of variable density such as compressible gases or fluids of variable viscosity such as non-Newtonian fluids, special rules apply.
42.
For a Newtonian fluid, the viscosity, by definition, depends only on temperature and pressure, not on the forces acting upon it.
43.
Using these properties, the Navier Stokes equations of motion, expressed in tensor notation, are ( for an incompressible Newtonian fluid ):
44.
Unfortunately we didn't have time to try the non-Newtonian fluid, so I now have a bag of cheap flour lying around.
45.
With Newton s second law, Newtonian fluids assumption and Stokes hypothesis, the original fluid momentum equations are derived as the Navier-Stokes equations.
46.
The coefficient of proportionality is called the fluid's viscosity; for Newtonian fluids, it is a fluid property independent of the strain rate.
47.
:There are a lot of Non-Newtonian fluids out there-and the precise classification of which is of which type is a bit tricky.
48.
The large class of fluids whose viscosity changes with the strain rate ( the relative flow velocity ) are called non-Newtonian fluids.
49.
So sometimes they do a second step, called anti-icing, in which they spray the plane with a mix of glycol and non-Newtonian fluids.
50.
Properties investigated were in particular the non-Newtonian fluid flow for shear and elongation flow and the stress overshoot maximum after abrupt start of the flow.
