Experimental research on the effect of suspended sediment stratification on turbulence characteristics

作者：Huang, Rui; Zhang, Qinghe^*; Zhang, Wei^*; Li, Zhanhai

来源：Estuarine, Coastal and Shelf Science, 2022, 278: 108128.

DOI：10.1016/j.ecss.2022.108128

• Suspended sediment stratification
• Turbulence characteristics
• Stratification parameter
• Oscillating grid
• Optical fibre sediment concentration meter

A double-layer transverse oscillating grid for a flume was designed and manufactured, in order to generate approximately isotropic homogeneous turbulence, and allowing the effect of suspended sediment stratification on turbulence characteristics to be studied experimentally. In the experiment, the diachronic variations in turbulence and suspended sediment concentration were measured synchronously using an Acoustic Doppler Velocimeter and a multichannel optical fibre suspended sediment concentration meter. The effect of suspended sediment stratification on turbulence was analyzed in relation to changes in turbulence characteristics, such as root mean square velocity and turbulence intensity. The experimental results confirm that suspended sediment stratification can suppress turbulence and weaken turbulence intensity, and the degree of turbulence suppression is related to the suspended sediment concentration gradient and turbulence intensity. By analogy with the dimensionless Richardson number that characterizes stratification in common ocean models, we define a dimensionless stratification parameter that characterizes the degree of stratification related to turbulence in an oscillating grid. The analysis shows that the turbulence suppression rate is closely related to the stratification parameter in sediment-laden flows. The correlation between turbulence suppression rate and stratification parameter may be obtained using a fitting technique.

• 单位
  河海大学; 天津大学