| Project/Area Number |
09450185
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
水工水理学
|
|---|
| Research Institution | Hokkaido University |
|---|
Principal Investigator |
ITAKURA Tadaoki Hokkaido Univ., Grad. School of Eng. Prof., 大学院・工学研究科, 教授 (70001138)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YAMASHITA Yasumasa Hokkaido development consultant, 研究主任
MORI Akio Hokkaodo Univ., Grad School of Inst., 大学院・工学研究科, 助手 (00001339)
SHIMIZU Yasuyuki Hokkaodo Univ., Grad. School of Eng., Asso. Prof., 大学院・工学研究科, 助教授 (20261331)
MUNETA Naruhiko Hokkaido development bureau, 研究員
NISHIMOTO Naoshi Nihon construction consultant, 研究主任
|
|---|
| Project Period (FY) |
1997 – 1999
|
| Project Status |
Completed (Fiscal Year 1999)
|
| Budget Amount *help |
¥9,600,000 (Direct Cost: ¥9,600,000)
Fiscal Year 1999: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥7,300,000 (Direct Cost: ¥7,300,000)
|
|---|
| Keywords | numerical tool / deformation of river bed / steep river / river construction / hydraulic jump / bore / Froude number / 3D-model / 都市急流河川 |
|---|
| Research Abstract |
Multi-dimensional characteristic theory has some arbitrariness in choosing the direction of rays. From the point of numerical approach two model were presented. The first is plane wave model, which was proved to have good performance for the transition of critical states of 2D-varied-width-flow by comparing with ID-theory. The second is stream line model, which is more easy to treat and more practical for complicated systems, for example, bed deformation problem, than the first model, and was applied to the free surface flows. Since, the moving coordinates fitted to the free surface was transformed into the local migrating Cartesian coordinate, the system was easily applied to the characteristic theory and a numerical model with simple upwind scheme was developed.
Two 1D model based on FDS was developed. The first model is a flow model using primitive variables based on the VKI theory and a good remedy for the Entropy condition was presented. The second model is a bed deformation model and it was found that the hydraulic jump and the problem of the control section disappear in this model. This comes from vanishing of zero-characteristic-velocity which is observed in the analysis of the shallow water equation. It seems that the interaction between the flow the bed load divides the wave of the zero-characteristic-velocity of the flow without bed load into two waves, + sign wave and - sign wave for all F. This division causes two no-zero-velocity waves. This finding is very important in practical application to analyze the bed deformation in the steep river. Since the characteristic equation of this system is based on 3rd-order equation, it is a little bit cumbersome to treat. However, a simple approximate method which utilized the usual one was introduced and proved to be valid a little bit away form the critical point.
|
