1993 Fiscal Year Final Research Report Summary
Development of Measuring System of Sediment Discharge by means of Acoustic and Ultrasonic Imaging Methods
| Project/Area Number |
03555117
|
|---|
| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Hydraulic engineering
|
|---|
| Research Institution | Setsunan University (1993)
Kyoto University (1991-1992) |
|---|
Principal Investigator |
SAWAI Kenji Setsunan University, Department of Civil Engineering, Professor, 工学部, 教授 (70109073)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Kuniaki Sabo Technical Center, Section of Planning and Research, Chief Researcher, 企画部, 主任研究員
SAWADA Toyoaki Kyoto University, Hotaka Sedimentation Observatory, Associate Professor, 防災研究所, 助教授 (60027258)
TANIGUCHI Shin-ichi Shiga University, Department of Information Management, Associate Professor, 経済学部, 助教授 (90144279)
TAKAHASHI Nobuyuki Kyoto University, Department of Electronics, Instructor, 工学部, 助手 (70206829)
MIZUYAMA Takahisa Kyoto University, Department of Foresty, Associate Professor, 農学部, 助教授 (00229717)
|
|---|
| Project Period (FY) |
1991 – 1993
|
| Keywords | Sediment Discharge Measurement / Acoustic Measurement / Ultrasonic Imaging / Mountain Stream / Sediment Control / 流砂 |
|---|
| Research Abstract |
(1) Acoustic Monitoring of Collision and its Data Processing
A new idea for estimation of sediment discharge was derived, in which the statistic property was obtained by a simulation of the motion of individual particles. Based on this idea, some simulation was carried out to obtain the statistic distribution of the relative momentum in collision between gravels and pipe under various combination of pipe diameter, gravel size and some hydraulic parameters.
On the other hand, some flume experiments were carried out, in which the limit condition of the distinction of the individual collision was found out. And it was considered which kind of data processing is most effective to estimate sediment discharge
(2) Ultrasonic Image Recording of Sediment Transport and the Signal Processing
It is shown that the static background noise and various noises arising from the ultrasonic multiple scattering from surroundings can be reduced by the method of assymmetric difference. Next, the size of sediment can be estimated from the data in the spatial frequency domain which is given by the Fourier transform of one dimensional data.
From the time series of frequency spectra acquired by simultaneous measurement at two locations we can calculate their cross-correlations to estimate the speed of flowing sediment. By this simultaneous measurement at two locations it becomes possible to estimate the sediment size even if a miss measurement occurs at either location.
A new method of measurement based on the wavelet transformation has been developed in the present work : we can estimate the sediment size with multiple resolution and at the same time their positions across the channel as well. At the moment, however, there is no fast algorithm in the wavelet method like FFT in the Fourier method, so that a fast computer is indispensable for the wavelet analysis. Therefore, a further problem is how to develop and improve the wavelet method to be suitable for a real time processing.
|
