Estimation of turbulence intensity within a highly-aerated turbulent flow is challenging. A possible way is to record bubble arrival information using intrusive phase-detection probes, but the derivation of velocity variation is subject to the correlation and de-correlation of the signals, especially in highly-turbulent and rapidly-varied flows with complex bubble transport such as in hydraulic jumps. Although attempts have been devoted to the improvement of data processing, it is difficult to assess the existing approaches in strong hydraulic jumps due to the lack of alternative measurement techniques applicable to the internal air-water flow region. In this letter, a substantial amount of work is devoted to manual analysis of instantaneous interfacial velocity in strong hydraulic jumps, and the velocity variation results are compared with the results of full-signal cross-correlation and adaptive-window cross-correlation approaches, to evaluate their performance in approximating the velocity turbulence. The manual results are validated in terms of the time-averaged velocity. The interfacial turbulence intensity is suggested to be greater than the water-phase velocity turbulence, typically between 20% and 40% in the unidirectional jet-shear region. Overall the manual results agree better with the calculation of adaptive-window cross-correlation technique. The relevance of the signal decomposition processing is also discussed, and it is emphasized that the phase-detection-based approaches are subject to the limitations of one-dimensional measurements in a complex three-dimensional flow.

高度充气湍流中湍流强度的估计具有挑战性。一种可能的方法是使用侵入式相位检测探头记录气泡到达信息，但速度变化的推导取决于信号的相关性和去相关性，特别是在具有复杂气泡传输的高度湍流和快速变化的流动中，例如就像在水力跳跃中一样。尽管已致力于改进数据处理，但由于缺乏适用于内部空气-水流区域的替代测量技术，很难评估强水跃中的现有方法。在这封信中，大量的工作致力于手动分析强水跃中的瞬时界面速度，并将速度变化结果与全信号互相关和自适应窗口互相关方法的结果进行比较，以评估它们在逼近速度湍流方面的性能。手动结果在时间平均速度方面得到验证。建议界面湍流强度大于水相速度湍流，通常在单向射流剪切区的 20% 到 40% 之间。总体而言，手动结果更符合自适应窗口互相关技术的计算。还讨论了信号分解处理的相关性，并强调了基于相位检测的方法在复杂的三维流中受到一维测量的限制。