Grant-in-Aid for Scientific Research (A)
|Research Institution||Chuo University|
HINO Mikio Chuo University, Faculty of Policy Studies, Professor, 総合政策学部, 教授 (30016323)
村本 龍雄 日本科学工業株式会社, 第一製造部長
佐藤 行成 日本科学工業(株), 研究部・取締役, 部長
宇多 高明 建設省, 土木研究所・河川研究室, 室長
村本 竜雄 日本科学工業(株), 第一製造部, 部長
UDA Takaaki Ministry of Construction, Research Institute of Public Works. Head of Hydraulic
SATO Yukinari Nihon Kagaku Kogyo Co., Head of Research Division
MURAMOTO Tatsuo Nihon Kagaku Kogyo Co., Head of Manufacture Division
|Project Fiscal Year
1994 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥9,200,000 (Direct Cost : ¥9,200,000)
Fiscal Year 1996 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1995 : ¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1994 : ¥5,700,000 (Direct Cost : ¥5,700,000)
|Keywords||LASER sediment concentration meter / Computer Tomography / Inverse problem / Fourier expansion / Virtual-load method / 2次元瞬間土砂濃度計 / CTスキャン / レーザ計測 / 逆問題 / 二重フーリエ展開法 / 仮想荷重法 / グリーン関数 / 3次元瞬間土砂濃度計 / レーザシート / 乱流構造 / コヒーレント構造 / 洪水流|
Need for the instantaneous measurement of 2-or3-dimensional sediment concentration distribution are high in order to understand the mechanism of sediment transportation and bed configuration changes in rivers. However, at present time, the only means of sediment concentration detection is a device applying photo-electronic cell.
We intended to develop an instrument for instantaneous measurement of 2-or 3-D sediment concentration by applyng the CT (computer tomography) technique. Especially, the following items are aimed at ;
(1) The instrument must not distrib flow fields.
(2) The measurement is made instantaneously.
(3) The instrument should be compact and portable for use in laboratories as well as fields.
(4) The price of the instrument is as low as possible for use by common researchers.
A row of laser emitters is placed on a line parallel to the mean flow. Extenciton rate of laser intensity is measured and recorded by ray receivers positioned on an opposite site. The concentration field is expressed either by the double Fouries series (complex variable) or by the virtual plate and load method (which has been proposed by the head investigator, M.Hino, in 1975). The problem reduces to a kind of computer tomography of solving a system of linear simulaneous equations.
This instrument was constituted of a scanning multipoint laser light transmitting unit, a photo detection array and a data processing unit whose software is operated based on the principle of the inverse estimation. Some laboratory test for a real concentration field proved the usefulness of the instrument. The method of virtual load proved to be superior to the double Fourier series expansion. By the former method, a more complicated concentration field can be expressed by a lesser number of expansion coefficients, the errors included in measured LASER intensity are easily cancelled.