Friction drag from a turbulent fluid moving past or inside an object plays a crucial role in domains as diverse as transportation, public utility infrastructure, energy technology, and human health. As a direct measure of the shear-induced friction forces, an accurate prediction of the wall-shear stress can contribute to sustainability, conservation of resources, and carbon neutrality in civil aviation as well as enhanced medical treatment of vascular diseases and cancer. Despite such importance for our modern society, we still lack adequate experimental methods to capture the instantaneous wall-shear stress dynamics. In this contribution, we present a holistic approach that derives velocity and wall-shear stress fields with impressive spatial and temporal resolution from flow measurements using a deep optical flow estimator with physical knowledge. The validity and physical correctness of the derived flow quantities is demonstrated with synthetic and real-world experimental data covering a range of relevant fluid flows.

翻译：湍流流体掠过或流经物体时产生的摩擦阻力在交通、公共基础设施、能源技术以及人类健康等多个领域起着至关重要的作用。作为剪切诱导摩擦力的直接度量，壁面剪切应力的准确预测有助于民用航空的可持续性、资源节约和碳中和，以及血管疾病和癌症等医疗技术的改善。尽管壁面剪切应力对现代社会如此重要，但我们仍然缺乏能够捕捉瞬时壁面剪切应力动态的充分实验方法。在本文中，我们提出了一种整体方法，利用具有物理知识的深度光流估计器，从流动测量中推导出具有出色时空分辨率的流速和壁面剪切应力场。通过涵盖一系列相关流体流动的合成和真实实验数据，验证了所推导流动量的有效性和物理正确性。