Experimental Investigation of Cluster Bed-Form Formation Over Uniform Sediment
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Copyright: © 2020 Masoud Karbasi, Mohammad H. Omid and Javad Farhoudi. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Problem statement: Cluster microforms are a type of small scale bed-form found in the surface layer of some gravel bed rivers. These bed-forms are comprised of discrete, organized groupings of particles that sit above the average elevation of the surrounding bed. As part of the structural organization of the bed, clusters are believed to impact the local dynamics of the fluvial system through the feedback process involving the flow field, entrainable sediment and stable bed morphology. Approach: In this study, flow and sediment characteristic measured at a laboratory flume and the presence or absence of clusters at each of these tests was recorded. A statistical analysis using logistic regression was performed to examine the correlation between the occurrence of clusters and various non-dimension combinations of measured variables. Results: It was found that the best parameters for predicting the clusters presence are gd2u/hU2avg and gd2u/U2avg. In two parameters analysis it was found that clustering was best predicted by gd2u/U2avg and τb/ρU2avg. Conclusion: It is thought that these parameters work best at predicting the presence of clusters because they are descriptive of hydraulic and sedimentary conditions of tested reach.
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- Gravel-bed rivers
- cluster prediction