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

浅层流动不是简单的，它们包含重要的形态不均匀，导致复杂的流动结构。在流动截面有相当大的横向变化的情况下，可能会形成大而缓慢的流体循环体积：浅死区。这些区域对溶解物质的质量传输和泥沙传输有重大影响。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，因此它们是为河流恢复目的而人工创造的。目前，由于缺乏对其流动动力学的了解，以及对局部几何形状和来流特性的依赖，它们的流动结构和对传质的影响还不能完全预测。这项工作旨在加深对浅水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表征。这些目标将通过一系列示意性实验室实验来实现，这些实验侧重于简单死区(港湾状)和死区序列(例如，河流丁坝)，用于浮现和淹没条件。这些实验将使用先进的立体粒子跟踪测速技术，以及同步的压力和水位传感器。这项工作有望成为第一批对浅水死区流动结构进行试验性三维描述的工作之一，并为改进处理浅水死区流动动力学的流体力学模型奠定基础。

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.