A Fluid Dynamics Laboratory in the Field: a study on shallow mixing layers at confluent and recirculating river flows under natural yet simplified conditions

河流中的湍流控制着复杂的混合和运输过程，对河流系统的功能和可持续管理的许多方面至关重要，因此代表了准确定量评估的挑战。拟议的研究旨在将浅层剪切流的分析扩展到更高的雷诺数和现实的流动条件，并测试最近开发的模型，作为预测方案的基础，促进速度场、湍流特征、河流汇合处和工程建筑的混合计算。本研究采用单探针和多探针技术，扩展粒子跟踪测速方法，对湍流进行现场物理模拟实验和测量研究。现场尺度的物理模拟意味着在一条低地河流的直浅河段建造汇合流和沟槽，并进行简化，以便控制实验条件。使用一些标准计算流体力学代码进行数值模拟，将有助于理解如何为这些复杂流动制定边界条件。拟议的研究将汇集德国柏林IGB团队提供的现场方法方面的专业知识，以及荷兰代尔夫特理工大学团队开发的先进实验室调查和数值模拟方法。

Turbulent flows in rivers govern complex mixing and transport processes crucial for many aspects of functioning and sustainable management of fluvial systems, hence representing the challenge of accurate quantitative assessment. Proposed research is aimed to expand the analysis of shallow shear flows toward both higher Reynolds numbers and realistic flow conditions, and to test recently developed models as the basis for predictive schemes facilitating computations of velocity fields, characteristics of turbulence, and mixing at river confluences and engineering constructions. The research is designed as a field-scale physical modeling experiment and measurement study of turbulence with one- and multi-probe techniques expanded with methods of particle tracking velocimetry. Field-scale physical modeling implies the construction of converging flows and groynes in a straight shallow reach of a lowland river with simplifications allowing to control the experimental conditions. Numerical simulations with some standard computational fluid dynamics codes will provide understanding on how to formulate the boundary conditions for these complex flows. The proposed research will gather together the expertise in field methods provided by the German team of IGB, Berlin and the advanced methods of laboratory investigation and numerical simulations developed by the Dutch team of TU Delft.