Singapore: World Scientific Publishing Co. Pte. Ltd.
Abstract:
In this study a simple pulsatile jer flow with two separate pulse frequencies of 1.33 Hz and 2.0 Hz, which respectively correspond to heart rates of 80 and 120 beats per minute under physiological conditions, was used to measure the major principal Reynolds shear stress and turbulence length scales in the flow. Although the Reynolds numbers during the peak phases of the pulsatile flows, namely Re = 55800 and 58400, are apparently larger than those of steady flows with Re = 22000, 28500, and 35000 [1], the maximum major principal Reynolds shear stress values measured during the peak phases of the pulsatile flows are significantly smaller. A value of 0.0065 was obtained in this study, while 0.0093 was measured in the steady flows, differing by approximately 40%. On the other hand, the turbulence length scales in both kinds of flow fields are relatively similar. This shows that using a steady jet flow to represent the peak phase of pulsatile flow while studying artificial prosthe ses could cause an overestimation of the turbulence stress values.
