Accurate wall-shear stress (WSS) in-vitro measurements within complex geometries such as the human aortic arch under pulsatile flow are still difficult to achieve, meanwhile such data are important for classifying impacts of prosthetic valves on aortic walls. Micro-cantilever beams can serve to sense the WSS in such flows for applications in in-vitro flow tester. However, within pulsatile flows and complex 3D curved geometries such as the aortic arch, the flexible sensor structures are subject to oscillating boundary layer thickness and profile shape, which may not have been taken into account in the calibration procedure. The fluid–structure interaction is sensitive to these changes, thus reflecting also the flow-induced deflection of the sensor tip which is actually the sensing signal. We develop herein a methodology for in-situ calibration of the response of the sensors directly in the complex geometry of the aortic arch, assisted by reference data from numerical simulations of the flow under the same boundary conditions. For this procedure, a quick exchange of the heart valve in the tester with a tubular insert is done to provide a smooth contour in the curved aorta model. Arrays of 500 $\mathrm{\mu }$m long micro-pillar WSS sensors in the aorta model are calibrated under physiological pulsatile flow and used then for mapping the WSS evolution in the arch induced by two different heart valve, showing their difference of impact. The developed methodology completes the in-house built in-vitro flow tester with a reliable WSS measurement technique and provides a unique hydrodynamic testing facility for heart valve prostheses and their impact on the WSS distal along the aortic walls.

在脉动流下的人体主动脉弓等复杂几何结构内准确的壁剪切应力 (WSS) 体外测量仍然难以实现，同时这些数据对于对人工瓣膜对主动脉壁的影响进行分类很重要。微悬臂梁可用于感测此类流动中的 WSS，以用于体外流动测试仪中的应用。然而，在脉动流和复杂的 3D 弯曲几何形状（如主动脉弓）中，柔性传感器结构会受到振荡边界层厚度和轮廓形状的影响，校准过程中可能没有考虑到这些。流体-结构相互作用对这些变化很敏感，因此也反映了传感器尖端的流动引起的偏转，这实际上是传感信号。我们在此开发了一种方法，用于在主动脉弓的复杂几何结构中直接对传感器的响应进行原位校准，并辅以来自相同边界条件下流动数值模拟的参考数据。在此过程中，用管状插入件快速更换测试仪中的心脏瓣膜，以在弯曲的主动脉模型中提供平滑的轮廓。500 个数组$\mathrm{\mu }$主动脉模型中的 m 长微柱 WSS 传感器在生理脉动流下进行校准，然后用于绘制由两个不同心脏瓣膜引起的弓中 WSS 演变，显示它们的影响差异。开发的方法使内部构建的体外流量测试仪具有可靠的 WSS 测量技术，并为心脏瓣膜假体及其对沿主动脉壁的 WSS 远端的影响提供了独特的流体动力学测试设施。