Al Sawaf Mohamad Basel, Kawanisi Kiyosi, Xiao Cong, Gusti Gillang Noor Nugrahaning, Khadami Faruq
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, 739-8527 Japan.
Water Resour Manag (Dordr). 2022;36(8):2589-2610. doi: 10.1007/s11269-022-03161-w. Epub 2022 May 4.
Understanding inflow dynamics in a dam lake forms the basis for optimal dam operation and management practices. However, methods pertaining to adequately determining negative inflows and addressing them, as well as quantifying uncertainties in dam inflow, have been scarcely investigated. In this study, the inflow was observed using two pairs of fluvial acoustic tomography (FAT) systems placed diagonally in a dam lake, forming a crossed-shaped pattern. The "travel-time" principle is the primary approach for measuring the inflow by FAT. The novelty of this study is in discussing the inflow characteristics within a slow water-flow environment monitored by FAT. Based on the reciprocal sound transmission, we upgraded an equation to estimate the flow direction; this newly proposed generalized equation can be used in a fluctuating flow environment. We also discussed the sound propagation characteristics for slow flow velocities. Finally, we demonstrated that a small inaccuracy in the acoustic signal, even by a sub-millisecond, can cause significant errors in measurements. One of the novel findings of this study is the detection of internal waves using the improved flow direction equation and acoustic travel-time records. Overall, this study presents a promising approach for inflow measurements under extremely slow flow conditions.
The online version contains supplementary material available at 10.1007/s11269-022-03161-w.
了解堰塞湖的入流动力学是优化大坝运行和管理实践的基础。然而，关于充分确定负入流并加以处理，以及量化大坝入流不确定性的方法，几乎没有得到研究。在本研究中，使用两对沿对角线放置在堰塞湖中的河流声学层析成像（FAT）系统来观测入流，形成十字形图案。“传播时间”原理是FAT测量入流的主要方法。本研究的新颖之处在于讨论了FAT监测的缓水流环境中的入流特征。基于互易声传播，我们改进了一个用于估计流向的方程；这个新提出的广义方程可用于波动流环境。我们还讨论了缓流速下的声传播特性。最后，我们证明了声学信号中即使是亚毫秒级的小误差也会在测量中导致显著误差。本研究的一个新发现是利用改进的流向方程和声传播时间记录检测内波。总体而言，本研究提出了一种在极缓流条件下进行入流测量的有前景的方法。
在线版本包含可在10.1007/s11269-022-03161-w获取的补充材料。
