The application of the acoustic Doppler velocimetry (ADV) technique to backward-facing step flows is very scarce in the literature. This work aims at investigating the applicability of the ADV technique to flows over a backward-facing step, at various Reynolds numbers to capture different flow regimes, and to provide reliable data which can be used to validate numerical models. The ADV was used in a laboratory flume and a customized numerical code was developed, which implements a methodology to post-process the ADV records. The normalized mean streamwise velocity and turbulence profiles were compared with classical results measured using a laser Doppler velocimeter and a high correlation was found. The ADV measurements showed accurate results regarding the streamwise velocity profiles, the turbulent shear stress and the reattachment length. Thus, ADVs can be used to characterize separated flows with good accuracy providing that an adequate post-processing is made to the acquired data. The errors obtained by the uncertainty analysis were relatively low, in general.

中文翻译：

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向后台阶上流动的声学多普勒测速测量

声学多普勒测速 (ADV) 技术在后向阶梯流中的应用在文献中非常少见。这项工作旨在研究 ADV 技术在向后台阶上流动的适用性，以各种雷诺数捕获不同的流态，并提供可用于验证数值模型的可靠数据。ADV 用于实验室水槽，并开发了定制的数字代码，该代码实施了一种对 ADV 记录进行后处理的方法。将归一化的平均流向速度和湍流剖面与使用激光多普勒测速仪测量的经典结果进行比较，发现了高度相关性。ADV 测量显示了关于流向速度剖面、湍流剪切应力和再附着长度的准确结果。因此，只要对采集的数据进行充分的后处理，ADV 可用于表征具有良好精度的分离流。一般而言，不确定度分析获得的误差相对较低。