Study on behavior wind-induced flow and water quality in a density stratified closed water area with aquatic plants

水生植物密度分层封闭水域风生流及水质研究

基本信息

批准号：
14360145
负责人：
MORI Ken
金额：
$ 7.3万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14360145/
关键词：
closed water area aquatic plant density stratified flow wind induced flow entrainment phenomenon turbulent structure water quality dissolved oxygen 浮葉性植物密度2成層溶存酸素日サイクル変動

项目摘要

Water environmental dynamics in closed water areas with density stratify such as ponds, reservoirs, lakes and estuaries are effected by turbulent flows based on mechanical and thermal disturbances. The thermal disturbance consists of lighting and heating based on solar radiation in the daytime and cooling based on emission at the night. The mechanical disturbance of wind induced flow and wind wave generated by wind action on the surface. We considered the mechanical disturbance of wind induced flow was generated by wind action on the surface in the closed water areas. An experimental investigation of turbulent entrainment induced by the mechanical disturbance was carried out in a laboratory wind -wave tank. We considered that the occupying rate of the floating water plants to the water surface affected on the turbulent entrainment in the closed water area. The results indicated that the existence the floating water plants contributed to make a significant effect on the scale of the turbulent entrainment. It was also found that the entrainment velocity depended on the Richardson number to the power of-3/2, the stability parameter of density stratified fluid flow. The following conclusions can be drawn : (1).From the experiment of entrainment velocity, the increase of the covered rate β of floating water plants decreases the entrainment velocity of the upper layer. (2).From the experiment of turbulent structure, the increase of the covered rate of floating water plants decreases the amount of turbulent energy. (3).The increase of the covered rate β of floating water plants decreases the turbulent energy of the upper layer that is produced at the surface. As the turbulent energy is transformed into potential energy, a close relationship between the decrease of entrainment velocity and the turbulent structure is clearly established.

池塘、水库、湖泊和河口等具有密度分层的封闭水域的水环境动力学受到基于机械扰动和热扰动的湍流的影响，其中热扰动包括基于白天太阳辐射的照明和加热以及基于白天的冷却。风诱发流和风波对水面的机械扰动我们对封闭水域中风对水面的作用产生的机械扰动进行了实验研究。在实验室风浪池中对机械扰动引起的湍流夹带进行了研究，认为漂浮水草对水面的占据率对封闭水域内湍流夹带的影响。漂浮的水植物对湍流夹带的规模产生了显着的影响，还发现夹带速度取决于密度分层流体的稳定性参数理查森数的-3/2次方。可以得出以下结论： (1)从夹带速度的实验来看，漂浮水草覆盖率β的增加降低了上层的夹带速度。，漂浮水草覆盖率的增加降低了湍流能量的大小 (3)。漂浮水草覆盖率β的增加降低了表面产生的湍流能量。湍流能转化为势能，夹带速度的减小与湍流结构之间的密切关系清晰可见。