ON THE STABILITY OF THE JEFFERY-HAMEL FLOW

The Jeffery-Hamel flow is analyzed by making use of a mechanical analo gy. The solutions are generated by a finite element method, for the co rresponding least action principle and are valid for any width of the channel. Then, the Galerkin method is used to study the linear and tem poral stability of some flows for small widths of the channel. An argu ment is given to show that pure inflow should be unstable for small wi dths of the channel, a result which is corroborated by our numerical c alculations. We find that the flows IOI and IO are unstable for Reynol ds numbers near zero. A stability window for some asymmetric flows and certain widths is also found. (C) 1997 American Institute of Physics.