Biconical geometries in rheometers: Exact solution for the flow field and implications for the design of measuring systems.

Rheometric investigations using cone-plate geometries are one of the most basic flow situations. This publication presents our findings on the analytic solution for the velocity field in the gap between two conical boundaries for rheometric flows, which has been designed by us and is referred to as "cone-pan." The formulae are derived from the Navier-Stokes-equation in a suitable coordinate system and found in accordance with previous findings. We experimentally verify the formulae for Newtonian fluids and investigate in brief the limits of stability of this flow experimentally and from a literature discussion. A qualitative discussion of non-Newtonian effects, based on the available literature, is provided for reasons of completeness.