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：湍流流体流经物体表面或内部时产生的摩擦阻力在交通、公共基础设施、能源技术及人类健康等诸多领域扮演着关键角色。作为剪切诱发摩擦力的直接度量，壁面剪切应力的精确预测不仅有助于实现民用航空领域的可持续性、资源节约与碳中和目标，还能提升血管疾病和癌症的医疗效果。尽管其对社会发展具有如此重要性，但目前我们仍缺乏能够捕捉瞬时壁面剪切应力动力学的有效实验方法。本研究提出了一种整体性方法，通过融合物理知识的深度光流估计器，从流动测量数据中获取具有卓越时空分辨率的速度场与壁面剪切应力场。通过覆盖多种相关流体流动的合成数据与真实实验数据，验证了所导出流动量的有效性与物理正确性。