Suspended and bedload transport in an open channel laboratory flume

Notwithstanding the large number of studies on bedforms such as dunes and
antidunes, performing quantitative predictions of bedform type and
geometry remains an open problem. Here we present the results of
laboratory experiments specifically designed to study how sediment supply
and caliber may impact equilibrium bedform type and geometry in the upper
regime. Experiments were performed in a sediment feed flume with flow
rates varying between 8 l/s and 15 l/s, sand supply rates varying between
0.6 kg/min and 16 kg/min, uniform and non-uniform sediment grain sizes
with geometric mean diameter varying between 0.22 mm and 0.87 mm. The
experimental data and the comparison with datasets available in the
literature revealed that the ratio of the volume transport of sediment to
the volume transport of water Qs/Qw plays a prime control in the
equilibrium bed configuration. The equilibrium bed configuration
transitions from washed-out dunes (lower regime), to downstream migrating
antidunes (upper regime) for Qs/Qw between 0.0003 and 0.0007. For values
of Qs/Qw greater than those typical of downstream migrating antidunes, the
bedform wavelength increases with Qs/Qw. At these high values of Qs/Qw
equilibrium bed configurations with fine sand are characterized by
upstream migrating antidunes or cyclic steps, and significant suspended
load. In experiments with coarse sand, equilibrium is characterized by
plane bed with bedload transport in sheet flow mode. Standing waves form
at the transition between downstream migrating antidunes and bed
configurations with upstream migrating bedforms.

尽管学界已针对沙垄（dunes）与逆行沙波（antidunes）等床面形态（bedforms）开展了大量研究，但对床面形态类型与几何特征进行定量预测仍是一项尚未解决的开放性难题。本研究展示了专为探究上层流态下泥沙补给量与粒度如何影响平衡床面形态的类型与几何特征而开展的水槽实验结果。实验在供沙水槽中开展，实验参数涵盖：流量范围为8 l/s至15 l/s，供沙速率范围为0.6 kg/min至16 kg/min，泥沙粒径包含均匀分布与非均匀分布两种类型，几何平均粒径介于0.22 mm至0.87 mm之间。通过对实验数据的分析，并与公开文献中的数据集进行对比，研究发现：泥沙体积输移率与水流体积输移率的比值Qs/Qw是控制平衡床面构型的核心因素。当Qs/Qw介于0.0003至0.0007之间时，平衡床面构型会从冲蚀沙垄（对应下层流态）转变为顺行迁移的逆行沙波（对应上层流态）。当Qs/Qw高于顺行迁移逆行沙波的典型阈值时，床面形态的波长会随Qs/Qw的增大而增大。在Qs/Qw较高的工况下，采用细沙的实验组中，平衡床面构型以逆行迁移的逆行沙波或周期性台阶床形为典型特征，且伴随显著的悬移质输移。而采用粗沙的实验组中，平衡床面构型表现为平整床面，且推移质以片流方式进行输移。在顺行迁移逆行沙波与逆行迁移床面形态的床面构型过渡区域，会形成驻波。

搜集汇总

背景与挑战

背景概述

该数据集包含2022年发布的实验室水槽实验数据，旨在研究沉积物供应和粒径对开放渠道中悬浮和床沙输运及河床形态的影响。实验涉及水流速率、沉积物供应速率和粒径变化，数据包括河床高程、水面高程和速度剖面测量，用于分析沉积物与水输运比例对河床配置的控制作用。