Study on Effects of Roughness Patterns on Turbulent Structure though Field Measurements

由于近年来河流整治的广泛目的，我们应该更多地了解各种粗糙度类型的水流结构。实际上，山区河流整治需要掌握相对淹没小的水流知识。在河流中设计各种类型的构筑物时，水流必须经历不同类型的空间粗糙度变化，因此需要研究湍流对空间粗糙度变化的瞬态过程。河道环境整治，有植被的河道流量要准确评价。在本研究项目中，将理论分析和实验室基础实验相结合的方法与湍流的现场测量相结合。风速计和数据记录和处理系统的最新发展使现场测量相对容易。我们开发了利用电磁风速仪进行湍流现场测量的系统，并在河流或灌溉渠中精心选择了测量点。选取了相对浸没度小的流动、倾斜条形粗糙度上的流动、植被上的流动、床层粗糙度空间变化的流动、横断面上有植被带的流动，并通过野外和实验室的测量结果进行了比较，证实了湍流现象的相似性。利用在野外和实验室获得的宝贵数据，通过数据分析以及与实验室数据和分析或数值方法结果的比较，研究了明渠流动中粗糙度模式的影响。

Because of recent wide purpose of river improvements, we should know more about the flow structure with various patterns of roughness. In fact, river improvement in mountain regions needs the knowledge on the flow with small relative submergence. For designing various types of structures in rivers, the flow must experience various patterns of spatial change of roughness, and thus the transient process of turbulent flow for spatial change of roughness should be studied. The river improvement with special respect with environments, the flow with vegetation should be accurately evaluated.In this research project, the approach based on theoretical analysis and fundamental experiments in laboratories was coupled with field measurements of turbulence. Recent development of anemometers and data-recording and processing system have made field measurements comparatively easy. We have developed the system of field measurements of turbulence with aid of electromagnetic anemometers, and carefully selected the measuring sites in rivers or irrigation canals. The flow with small relative submergence, hekicoidal fluid motion of flow over skew arrangement of strip roughness, the flow over vegetation, the flow with spatial change of bed roughness, the flow with vegetation zone in a cross section have been selected and the measurements in fields and in laboratories have been compared to confirm the similarity of the turbulent phenomena. With valuable data obtained in fields and laboratories, the effects of roughness patterns in open-channel flows have been investigated through data analyses and comparison of the data with laboratory data and the results of analytical or numerical approaches.