Velocity profiles and streamlines of a revolution post-stenotic flow.

Velocity fields have been measured in models simulating arterial stenoses for continuous and revolution flows. A pulsed Doppler velocimeter allows for velocity readings in the entire tube and in the wall area. Streamlines are determined by numerical solving of the system of equations defining the current function. Velocity profiles and streamlines are presented and discussed either for steady or for unsteady flows, with different Reynolds numbers and variable degrees of stenosis. There is, in the wall area, a recirculating zone made of a well-defined rouleau. Its length varies increasingly according to the increasing severity of the stenosis. The stability of axial flow depends on the input profile, the degree of stenosis and the Reynolds number. Plotting streamlines allows to describe accurately the flow; its quantitative aspect offers advantages with respect to conventional visualization mode.