River, Estuarine and Coastal Engineering 本文へジャンプ
A/Prof. Kiyoshi Kawanishi
(Kiyosi Kawanisi)
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Welcome to River, Estuarine and Coastal Engineering, Hiroshima University.

Streamflow is an important hydrological factor in river and coastal planning/management, control of water resources, and environment conservation. Therefore, it is a key issue to establish the measurement method and subsequent technology for measuring stream flow.
Fluvial Acoustic Tomography (FAT) system, which is developed by my research group in Hiroshima University, has a few noticeable functions represented by the accurate measurement of travel time using a GPS clock and the attainment of high signal-to-noise ratio as a result of transmission signal modulation by the 10th order M-sequence. As shown in the above aerial photo, a couple of transducers of central frequency of 30 kHz are installed diagonally across a river.


Example of an estuarine cross-section: contour plot of sound speed distribution and a result of ray simulation (ray pattern).
The cross-sectional average velocity of the river stream can be estimated from the travel time difference data, obtained along the ray paths that cover the channel cross-section.

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