Shallow dead zone dynamics: Experimental description and analysis of the three-dimensional flow structure of single dead zones and dead zone sequences, with special focus on their turbulent characteristics, coherent structures and water surface oscillatio

浅流并不简单，它们包含重要的形态不均匀性，从而导致复杂的流结构。当流动截面横向变化较大时，可形成大而缓慢的流体再循环体积：浅死区。这些带对溶解物质的质量输运和沉积物输运有主要影响。此外，它们的水流结构已被证明是刺激水生物种生长的重要因素，因此它们被人工创造用于河流恢复目的。目前，由于缺乏对其流动动力学的认识，以及它们对局部几何形状和来流特性的依赖，它们的流动结构和对质量输运的影响还不能完全预测。这项工作旨在提高对浅死区三维流动动力学的理解，包括湍流、相干结构和水面振荡的时空特征。这些目标将通过一系列的示意图实验室实验来实现，这些实验集中在简单的死区（类似港口）和死区序列（例如河流沟槽）上，用于浮现和淹没的条件。实验将使用先进的立体粒子跟踪测速技术，以及同步压力和水位传感器进行。预计这项工作将创建浅死区流动结构的第一个实验三维描述之一，并形成改进的流体动力学模型处理其流动动力学的基础。

Shallow flows are not simple, they contain important morphological inhomogeneities that lead to complex flow structures. In case of considerable lateral changes of the flow cross-section, large and slow recirculating volumes of fluid can be formed: the shallow dead zones. These zones have major effects on the mass transport of dissolved substances and on sediment transport. In addition, their flow structure has proven to be an important factor for stimulating the growth of the aquatic species, hence they are artificially created for river restoration purposes. Currently, their flow structure and the effects on mass transport cannot be totally predicted, due to the lack of knowledge of their flow dynamics, and their dependency on the local geometry and incoming flow characteristics. This work aims to improve the understanding of the three-dimensional flow dynamics of shallow dead zones, including the spatio-temporal characterization of turbulence, coherent structures and water surface oscillations. The goals will be achieved by a series of schematic laboratory experiments focusing on simple dead zones (harbor-like) and dead zone sequences (e.g. river groynes) for both the emerged and the submerged conditions. The experiments will be conducted using an advanced Stereo Particle Tracking Velocimetry technique, together with synchronous pressure and water level sensors. It is expected that this work will create one of the first experimental three-dimensional descriptions of the flow structure in shallow dead zones, and form the basis for improved hydrodynamics models dealing of their flow dynamics.