1998 Fiscal Year Final Research Report Summary
Tree-dimensional Measurement of Thrbulence Structure in Open Channel Flows by Flow Visualization and Picture Processing
| Project/Area Number |
08555131
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 展開研究 |
|---|
| Research Field |
水工水理学
|
|---|
| Research Institution | KYOTO UNIVERSITY |
|---|
Principal Investigator |
UENO Tetsuo Kyoto Univ., Disaster Prevention Res. Inst., Assistant, 防災研究所, 助手 (70027267)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
UTAMI Tadashi Wakayama Univ., Faculty of Systems Eng., Professor, システム工学部, 教授 (00027244)
|
|---|
| Project Period (FY) |
1996 – 1998
|
| Keywords | Open Channel Flow / Unsteady Flow / Compound Channel / Turbulence / Flow Visualization / Picture Processing / 動画像解析 |
|---|
| Research Abstract |
First, the large scale structure of turbulence in an open channel flow was examined by flow visualization and picture analysis. A horizontal cross-section of the flow was illuminated by a sheet of light and a pair of photographs ware taken in a short span of time using the 35 mm movie camera. Then the illuminated cross-section was quickly shifted upward and another pair of pictures ware taken. 15 pairs of photographs ware taken from the channel bed to the water surface during about 1 second. The photographs ware digitized by a CCD digital camera and velocity vectors ware calculated by multi-step correlation technique. Characteristic features of turbulence structures near the channel bed and in the upper layer ware elucidated based on the three-dimensional distribution of the velocity and the vorticity.
Secondly, the turbulence structures of the unsteady smooth open channel flow were examined by flow visualization and image processing. Based on the data obtained by the image processing, the characteristic features of the horseshoe vortex and parallel spiral flows with longitudinal axes ware elucidated.
Thirdly, the flow patterns in three types of meandering channels with compound cross-section were examined by flow visualization and image processing. Based on the data obtained by the image processing, the characteristic features of the large scale turbulence structures in the best type of meandering channels with compound cross-section ware elucidated.
|
