INITIATION OF TURBULENCE IN MODELS OF ARTERIAL STENOSES

The development of turbulence under both steady and pulsatile flow through models of arterial stanoses was studied experimentally. Stenoses were represented by three severely constricted rigid-walled models with different shapes. Model geometries included a streamlined shape, a hollowed plug with blunt ends, and a thin plate orifice. Velocity fluctuations were measured with hot-film probes. Results indicate that: (a) turbulence develops at Reynolds numbers well below the critical value for flow in an unobstructed tube; (b) the critical Reynolds number varies with a dimensionless frequency parameter, first becoming less stable and then more stable as the frequency parameter is increased; and (c) the critical Reynolds number depends on the shape of the obstruction with the orifice-type stenosis exhibiting the lowest value for the critical Reynolds number. © 1979.