Laboratory tests in a flow channel with scaled model dune (EbbSF)

Using experiments in the physical model, flow and turbulence processes caused by soil forms were investigated. For this purpose, laboratory tests were carried out in a flow channel with abstracted model dunes. For the collection of an extensive data set to describe the flow field above a soil shape, a model dune was used, whose geometry is oriented to dunes observed in the Weser with so-called Ebb Slip Face (EbbSF). The dune dimensions and hydrodynamic sizes were scaled in 1:10 scale according to Froude. The model dune was installed as a two-dimensional single-thin and exposed to a unidirectional flow of constant velocity and constant water level. Due to the use of corrugated sheet for the production of the model dune, the natural surface roughness of real dunes was not replicated. For the flow measurements, a narrow distribution of the measuring positions was chosen in the area above and behind the model body, so that a comprehensive raw dataset with high-frequency acoustic flow data is provided.本研究通过物理模型试验，针对土体床面形态诱发的流动与紊动过程展开了系统探究。为此，本研究在布设了简化模型沙波的流动水槽中开展了室内试验。 为构建一套用于描述床面形态上方流场的完备数据集，本次试验采用的模型沙波，其几何形态参照取自威悉河（Weser）观测到的、带有退落滑移面（Ebb Slip Face, EbbSF）的天然沙波设计。该模型沙波的几何尺寸与水力学参数均按1:10的比例，依据弗劳德（Froude）相似准则进行缩放。模型沙波以二维单薄型结构安装，被置于恒定流速、恒定水位的单向水流中。由于模型沙波采用波纹板制作，未还原天然沙波的天然表面糙率。 针对流动测量环节，本研究在模型体上方及后方区域采用了窄间距布设的测量点位，最终获取了包含高频声学流动观测数据的完整原始数据集。