Velocity and volume fraction measurements of granular flows in a steep flume

被引：0
作者：
SARNO L. [1 ,2 ]
PAPA M.N. [1 ]
CARLEO L. [1 ]
VILLANI P. [1 ,3 ]
机构：
[1] Department of Civil Engineering, University of Salerno, Via Giovanni Paolo II, 132, Fisciano
[2] Institute of Fluid Dynamics (FDY), Technische Universität Darmstadt, Otto-Berndt-Str. 2, Darmstadt
[3] University Consortium for Research on Major Hazards (CUGRI), Salerno, Italy Via Giovanni Paolo II, 132, Fisciano
来源：
Environmental and Engineering Geoscience | 2021年 / 27卷 / 02期
关键词：
Debris Flows; Granular Flows; Particle Image Velocimetry (PIV); Rheological Stratification; Stochastic-Optical Method (SOM); Volume Fraction;
D O I：
10.2113/EEG-D-20-00027
中图分类号：
学科分类号：
摘要：
Laboratory experiments on granular flows remain essential tools for gaining insight into several aspects of granular dynamics that are inaccessible from field-scale investigations. Here, we report an experimental campaign on steady dry granular flows in a flume with inclination of 35°. Different flow rates are investigated by adjusting an inflow gate, while various kinematic boundary conditions are observed by varying the basal roughness. The flume is instrumented with high-speed cameras and a no-flicker LED lamp to get reliable particle image velocimetry measurements in terms of both time averages and second-order statistics (i.e., granular temperature). The same measuring instruments are also used to obtain concurrent estimations of the solid volume fraction at the sidewall by employing the stochastic-optical method (SOM). This innovative approach uses a measurable quantity, called two-dimensional volume fraction, which is correlated with the near-wall volume fraction and is obtainable from digital images under controlled illumination conditions. The knowledge of this quantity allows the indirect measurement of the nearwall volume fraction thanks to a stochastic transfer function previously obtained from numerical simulations of distributions of randomly dispersed spheres. The combined measurements of velocity and volume fraction allow a better understanding of the flow dynamics and reveal the superposition of different flow regimes along the flow depth, where frictional and collisional mechanisms exhibit varying relative magnitudes. © 2021 Geological Society of America. All rights reserved.
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页码：245 / 257
页数：12
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