Flow regimes inside an expanding channel

The well-known Jeffery-Hamel similarity solutions describe two-dimensional radial flow of viscous fluid inside an expanding channel (wedge). At Reynolds numbers greater than a certain critical value $R_C$, the theoretical solution becomes non-unique, with the possibility of radial velocity profiles with alternating inflow/outflow. While our earlier experimental work\footnote{V.~Putkaradze, P.~Vorobieff, Phys. Rev. Lett. \textbf{97}, 144502 (2006).} confirms the absolute stability of the Jeffery-Hamel radial solution for $RR_C$ by altering the conditions at the outlet of the expanding channel.