Hydraulic jumps occur commonly in natural channels and energy dissipation systems of hydraulic structures in the violent transition from supercritical to subcritical flows. They are characterised by large flow aeration, high turbulence and strong fluctuations of the free surface and the jump toe. For free surface measurements, fast-sampling, fixed-point instruments such as acoustic displacement meters (ADMs) and wire gauges (WGs) are commonly used, while LIDAR technology is a relatively new method for recording instantaneous free surface motions of aerated flows. While each of these instruments has been shown previously to provide reasonable results for basic and advanced free surface properties, differences between instruments and experiments remain unexplained. To systematically analyse these differences, simultaneous laboratory experiments of aerated hydraulic jumps were conducted. Good agreement between the three instruments was obtained for basic free surface properties including elevations, fluctuations, skewness, kurtosis, and frequencies, as well as advanced free surface properties such as integral time and length scales. These new results indicate that any of these instruments can be used for the recording of free surface properties albeit the free surface integral scales are sensitive to the spacing of instruments. A key finding of this research was that differences between repeated experiments as well as previous studies were observed when using the visual jump toe for alignment. However, this bias could be resolved by using the mean jump toe location recorded with the LIDAR. Therefore, future research of the fundamental flow processes should simultaneously measure the instantaneous jump toe to provide more consistent results across studies.

在从超临界流到亚临界流的剧烈过渡中，水力跳跃通常发生在水力结构的自然通道和能量耗散系统中。它们的特点是通气量大，湍流大，自由表面和跳趾的剧烈波动。对于自由表面测量，通常使用快速采样的定点仪器，例如声位移计（ADM）和线规（WG），而LIDAR技术是一种相对较新的方法，用于记录充气流的瞬时自由表面运动。尽管先前已证明每种仪器都能为基本和高级自由表面性能提供合理的结果，但仪器和实验之间的差异仍无法解释。为了系统地分析这些差异，同时进行了充气液压跳跃的实验室实验。三种仪器之间的基本自由表面特性（包括高程，涨落，偏度，峰度和频率）以及高级自由表面特性（例如积分时间和长度标尺）都取得了良好的一致性。这些新结果表明，这些仪器中的任何一个都可以用于记录自由表面特性，尽管自由表面积分标尺对仪器的间距很敏感。这项研究的关键发现是，当使用视觉跳跃脚趾进行对准时，观察到重复实验与先前研究之间的差异。但是，可以通过使用LIDAR记录的平均跳趾位置来解决此偏差。所以，