| 槐文信,钟娅,杨中华.明渠漂浮植被水流内部能量损失和传递规律研究[J].水利学报,2018,49(4):397-403,418 |
| 明渠漂浮植被水流内部能量损失和传递规律研究 |
| Study on mechanism of energy spending and transition in open channel flow with suspended canopy |
| 投稿时间：2017-12-27 |
| DOI：10.13243/j.cnki.slxb.20171263 |
| 中文关键词: 漂浮植被 恒定均匀流 能量损失 能量传递 能量平衡 |
| 英文关键词: suspended canopy steady uniform flow energy spending energy transition energy balance |
| 基金项目:国家自然科学基金项目（51439007，11672213） |
|
| 摘要点击次数: 3022 |
| 全文下载次数: 1759 |
| 中文摘要: |
| 明渠漂浮植被会对河道过流能力造成不利影响。本文针对明渠漂浮植被均匀流，基于前人的过流断面能量平衡理论，研究明渠漂浮植被水流过水断面上的能量传递规律和能量平衡机理，推导出了断面上能量提供、能量损失和能量传递的表达式和相应能量累积的表达式，基于Plew的实测流速和切应力得到沿水深方向上的能量累积分布。结果表明在任意点和任意平面上，能量提供均等于能量损失与能量传递之和，断面上的能量损失主要集中在漂浮植被区，并且在植被区和非植被区的交界面达到最大。断面内总的能量传递为零，植被区和河床底部产生的能量提供不能弥补其能量损失，需要其他流区的能量不断地向这两个流区传递。在近壁流区，紊动动能累积值与能量传递累积值几乎相等，说明近壁流区内的绝大部分能量转化为紊动动能，非常小的一部分因抵抗近壁流区中的阻力而在该区内转化为热能损耗掉。 |
| 英文摘要: |
| Suspended canopy in open channel would have an adverse impact on flow capacity. Based on the previous theory of energy balance mechanism,this paper analyzed the energy transition law and energy balance mechanism of uniform flow section of open channel with suspended canopy,and has derived the expression of energy borrowing, energy spending, energy transition and relative accumulate values. Using Plew's experimental data of velocity and shear stress,the distribution of energy accumulation along the water depth has been obtained. The result shows that whether at a point or in a cross-section,the energy borrowing is equal to the sum of local energy spending and local energy transition. Energy spending is concentrated in the vegetated layer, reaching the maximum at the interface of vegetation and non-vegetation layers. The total energy transition in the cross section is zero. The energy borrowing in the vegetated layer and the riverbed cannot compensate for the energy spending. So surplus borrowed energy in other parts were needed to be transmitted to these two parts. In the near bed layer, the accumulate values of turbulent energy and energy transition are quite the same,which indicates that most of the energy in this layer is converted into turbulent energy, and only a very small part is converted into heat in order to withstand the resistance in the near bed layer. |
|
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |