After summarizing the basic equations, the type of the equations for theupper-convected Maxwell model and for the Jeffreys-type models is derived.It is shown that the corotational Maxwell model changes type which isunacceptable from a physical point of view. The Jeffreys-type models(including the Leonov model) have a drastic different type compared to theMaxwell models and are physically more appealing. Correct boundaryconditions are briefly discussed for a linearized upper-convected Maxwellmodel. The boundary conditions for the Jeffreys models are shown to be equalto the boundary conditions for the Navier-Stokes equations, supplemented byboundary conditions for all the extra stresses at the inflow boundary. Jumpconditions are derived for Jeffreys-type models. It is shown that in complexflows with sharp co! rners discontinuities may arise. Numerical methods arediscussed that take into account the special type of the equations.
|Titel||Proceedings of the 25th Meeting of the Dutch Association for Numerical Mechanics. Notes on Numerical Fluid Mechanics, Vol. 17.|
|Plaats van productie||Netherlands, Delft|
|Status||Gepubliceerd - 1987|