海山水平绕流与上升流

发布时间：2018-05-27 12:44

本文选题：海山 + 水平绕流　；参考：《北京交通大学》2015年硕士论文

【摘要】：海山是海洋地貌的重要组成部分,其存在可对周围海水的流动产生极大的影响。当海水流经海山时,一部分海水沿海山坡面流动形成上升流与下降流,其余部分绕过海山形成水平绕流。文献调研显示对海山上升流与水平绕流的研究并不充分。进一步深入研究海山附近的特有流动现象以及分析相应的动力机制,不仅是对流体力学基础理论知识的有益补充,也对海洋资源开发利用有现实意义。本文利用数值模拟的方法研究了不同雷诺数下海山的水平绕流和上升流,给出了大量非浸没海山和浸没海山的模拟算例。通过观察不同的雷诺数(Re)的算例发现：两类海山的水平绕流流动与均匀截面圆柱绕流有明显的差异,海山水平绕流尾迹区涡脱落的流态和强度在垂直方向有明显的变化,且依赖于雷诺数。值得注意的是,虽然浸没海山顶部以上的流动没有海山的直接阻挡,但对顶部以上的流动影响明显,浸没海山顶部以上的流动仍然存在类似绕流尾迹区涡脱落的流动现象。数值模拟结果表明：对于多数计算工况,在海山斜壁面上存在清晰的上升流与下降流,且二者分界清楚。进一步定量分析显示,分界点的高度有与雷诺数的依赖关系,并分别给出了非浸没海山和浸没海山上升流与下降流分界点高度的拟合计算公式。此外,也对两类海山的垂直流量进行了定量分析,分别给出了两类海山上升流强度(流量)对雷诺数依赖的拟合计算公式。本研究完成了非浸没海山和浸没海山的上升流与水平绕流的初步试算,描述了两类流动的主要特征,分析了相应的动力机制,并获得了计算上升流强度的定量关系式。然而,受时间所限,计算工况和算例还不充分,进一步大规模计算以及系统的理论分析和测量验证应该是后续工作的重点。
[Abstract]:Seamount is an important part of marine geomorphology, and its existence has great influence on the flow of sea water around it. When the sea water flows through the seamounts, a part of the sea water flows along the coastal hillside to form upwelling and descending currents, while the rest of the sea water flows around the seamounts to form a horizontal flow. Literature investigation shows that the study of seamounts upwelling and horizontal flow is not sufficient. It is not only a useful supplement to the basic theoretical knowledge of hydrodynamics, but also of practical significance to develop and utilize marine resources by further studying the peculiar flow phenomenon near seamounts and analyzing the corresponding dynamic mechanism. In this paper, the horizontal flow and upwelling of seamounts under different Reynolds numbers are studied by means of numerical simulation, and a large number of simulation examples of non-submerged seamounts and submerged seamounts are given. An example of different Reynolds number Re) shows that there is a significant difference between the horizontal flow around the seamounts and the flow around a circular cylinder with uniform section, and the flow pattern and intensity of vortex shedding in the wake region of the horizontal seamounts have obvious changes in the vertical direction. And depends on Reynolds number. It is worth noting that although the flow above the top of the seamounts is not directly blocked by the seamounts, the flow above the top of the seamounts is obviously affected, and the flow above the top of the seamounts is still similar to that of vortex shedding around the wake of the seamounts. The numerical simulation results show that there are clear upwelling and descending flows on the seamounts slope wall for most calculation conditions, and the boundary between the two is clear. Further quantitative analysis shows that the height of the boundary point is dependent on Reynolds number, and the fitting formulas for the height of the upwelling and descending seamounts are given, respectively. In addition, the vertical flow of two seamounts is quantitatively analyzed, and the fitting formulas for the dependence of the upwelling current intensity (discharge) on Reynolds number are given respectively. In this study, the preliminary calculation of upwelling and horizontal flow around unsubmerged seamounts and submerged seamounts has been completed, the main characteristics of the two flows have been described, the corresponding dynamic mechanism has been analyzed, and the quantitative relationship formula for calculating the upwelling intensity has been obtained. However, due to the limitation of time, the calculation conditions and examples are not sufficient. Further large-scale calculation, theoretical analysis and measurement verification of the system should be the focus of the follow-up work.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P731.2

【参考文献】