Velocity and wall-shear stress measurements of pulsatile flow of blood-analog fluids in elastic vessels

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Nowadays, pathological changes of human blood vessels are one of the major challenges of the modern health care system. In this context, the pulsating blood flow in elastic blood vessels and the resulting wall-shear stress distribution is one of the main factors that influences the mechanisms of arteriosclerosis and, hence, the development of arterial stenosis. Thus, from a medical point of view, precise predictions of the flow field and the unsteady wall-shear stress in human blood vessels are extremely important to assess the indication for surgery or to choose the most promising surgical intervention. For this, it is essential to analyze in detail the underlying problem of the fluid-structure interaction (FSI) of a pulsatile flow and an elastic vessel. From a fluid-mechanical perspective, this problem is characterized by a periodic flow, a vessel with complex geometry, and the interaction of a non-Newtonian fluid with the elastic vessel walls via the time-dependent wall-shear stress distribution. However, the hypothesis that the non-Newtonian rheological behavior of the fluid possesses a significant influence on the FSI via the unsteady periodic wall-shear stress and shear rate has not been investigated yet. It is the scope of this proposal to analyze the fluid-structure interaction between a pulsatile flow of a non-Newtonian, blood-analog fluid and an elastic vessel experimentally with high spatial and temporal resolution. The dilatation of and the flow field in straight and curved elastic vessels as well as symmetrical bifurcations will spatially be determined at high temporal resolution for physiological flow conditions, and the impact of the FSI on the velocity field, the vessel dilatation, and the wall-shear stress distribution will be quantified.