Application of nonlinear dynamics to hydro-geomorphology

非线性动力学在水文地貌学中的应用

• 批准号: 16360242
• 负责人: SHIMIZU Yasuyuki
• 金额: $ 9.41万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360242/
• 关键词: weakly nonlinear stability analysis; stream; double-row bar; dune; non-uniform sediment bed; 網状化; 画像計測; 数値計算モデル; 谷低平地; 中規河床波; 弱非線形解析; デューン; 復列砂州; 乱流; 浮遊砂; 平衡状態砂洲波高; 植生; 小規模河床波; 非線形解析; 圧力勾配; リップル; 乱流モデル

A weakly nonlinear analysis considering the interference between alternate bar and double-row bar has been developed. Findings show that when the two modes are on the same order, the mode cross interference controls development process of each wave and they cannot grow simultaneously. The development process of bars is strongly influenced of the mode cross interference. Hydraulic experiments and the weakly nonlinear analysis, by setting several hydraulic conditions under which either alternate bars or double-row bars formed, have been conducted to clarify a changing process of bar shape formed during flood at usual time. It is found that the channel shape at usual time is strongly affected by the bar shape during flood.Effect of unsteady characteristics of flow and vegetation growth on number of braided streams and temporal stability of streams has been studied. The results show that the number of streams decreases and temporal change of streams is suppressed with vegetation under unsteady flow conditions. Furthermore, dynamic characteristics of bars on bed with non-uniform sediment have been studied. The results show that bar geometry on bed with non-uniform sediment has been changed with time and does not approach equilibrium state.A new model was proposed taking proper account of the functional relation between the Froude number and the Shields number by revisiting the existing weakly nonlinear stability analysis of the transition of dune and flat bed regimes. It is found that, from the analysis, the dune-flat bed transition is characterized by subcritical bifurcation in the range of relatively small average bed slopes, and large velocity coefficient. In addition, Izumi extended the existing model of the inception of channels to the more general cases in which the base state slope profile is arbitrary given. The analysis shows that the spacing of channels is approximately one thousand times the depth of surface flow on slopes.

考虑到替代条与双行杆之间干扰的弱非线性分析已经开发出来。发现表明，当两个模式处于相同的顺序时，模式交叉干扰控制每个波的发展过程，它们不能同时生长。条形图的开发过程严重影响了模式交叉干扰。液压实验和弱非线性分析通过设置几个液压条件，在这些液压条件下进行了备用条或双行条，以阐明在通常时间在洪水期间形成的条形的变化过程。发现在洪水期间，通常在洪水期间的钢筋形状的通道形状受到了强烈的影响。已经研究了流动和植被生长的不稳定特征对编织溪流数量和溪流的时间稳定性的影响。结果表明，在不稳定的流动条件下，植被抑制了溪流的数量，溪流的时间变化被抑制。此外，已经研究了带有不均匀沉积物的床上杆的动态特性。结果表明，床上的条形几何形状随时间变化，并且不接近平衡状态。提出了一种新模型，可以正确考虑弗洛德号与盾牌数量之间的功能关系，并通过重新访问现有现有的弱点。沙丘和平床状态过渡的非线性稳定性分析。已经发现，从分析中，沙丘 - 平台床的转变的特征是在相对较小的平均床坡度范围内亚临界分叉和较大的速度系数。此外，izumi将通道的现有模型扩展到了更通用的情况，在该情况下，基本状态坡度是任意给定的。分析表明，通道的间距大约是斜坡上表面流量深度的一千倍。

项目成果

Analysis of stream channel geometry and physiographic formative process in valley flats

河谷滩地河道几何形状及地貌形成过程分析

• 发表时间: 2007
• 期刊: Annual Journal of hydraulic engineering, JSCE vol.51
• 作者: Nogami;T.;Watanabe;Y.;Yasuda;H.;Hasegawa;K.
• 通讯作者: K.

VALIDATION OF A NUMERICAL MODEL FOR FLOW AND BEDFORM DYNAMICS

流动和床形动力学数值模型的验证

• 发表时间: 2007
• 期刊: 水工学論文集 第51巻
• 作者: Sanjay Giri;Yasuyuki SHIMIZU
• 通讯作者: Yasuyuki SHIMIZU

Geometric Characteristics of bats on layers with rocks or cohesive material

岩石或粘性材料层上蝙蝠的几何特征

• 发表时间: 2007
• 期刊: River Sedimentation 10(印刷中)
• 作者: 山口里実;泉 典洋;泉 典洋;Hiroshi Takebayashi;Hiroshi Takebayashi
• 通讯作者: Hiroshi Takebayashi

初期河床に与える微小擾乱が砂州の発達及び砂州形状に及ぼす影響について

初始河床微扰动对沙洲发育及形态的影响

• 发表时间: 2007
• 期刊: 水工学論文集 第51巻
• 作者: 小林健介;清水康行;Sanjay Giri;渡邊康玄
• 通讯作者: 渡邊康玄

Weakly nonlinear stability analysis of fluvial dunes by the use of the mixing length turbulent model

基于混合长度湍流模型的河流沙丘弱非线性稳定性分析

• 发表时间: 2007
• 期刊: Annual Journal of Hydraulic Engineering Vol.50
• 作者: Izumi;N.
• 通讯作者: N.