Experimental study of physiological pulsatile flow in a curved tube

Abstract

In this paper, an experimental determination of the three-dimensional velocity distribution due to the physiological pulsatile flow of a Newtonian, incompressible fluid at various locations in a curved tube of circular cross-section is presented. Our results show four interesting features of the pulsatile flow development in the curved tube. First is the presence of a reversed flow along the inner wall of the tube during the diastolic (deceleration) phase of the pulsatile flow cycle. Second is that the flow does not appear to be fully developed in the curved tube through the cross-section whose L/a ratio is equal to 16·9, the final location at which measurements were made in this study, where L is the axial length and a is the radius of the curved tube. A third feature observed is the vacillation of the peak axial velocity across the horizontal diameter of the tube from the upstream to the downstream region in the curved tube. In the upstream region (L/a = 3·4), the maximum axial velocity measured occurred nearest to the outer wall. The maximum axial velocity shifted towards the inner wall in the middle of the tube (L/a = 10·2), while in the downstream region (L/a = 16·9), the maximum axial velocity measured was again near the outer wall. Finally, trapped vortical motions are observed to occur at the inner wall of the tube in the downstream region.