EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE EFFECT OF A VEGETATION ARRAY TO THE FLOW RESISTANCE AND CHARACTERISTICS

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Emre Haspolat-PhD Thesis.pdf

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2022-12-20

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Haspolat, Emre

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Vegetation canopies play a crucial role in aquatic living and ecology which makes them an essential part of rivers and waterways. In the present study, flow resistance due to submerged and emergent vegetation arrays having various densities was investigated experimentally and numerically under different hydraulic scenarios. A novel experimental setup having a drag plate was developed to measure drag forces acting on emergent and submerged vegetation arrays imitated by a group of rigid smooth cylinders in a staggered pattern. In the literature, studies were mostly conducted with large vegetation density, small stem diameter, and under low stem Reynolds numbers. On the other hand, the present study was performed with relatively lower vegetation densities, large stem diameter, and under high stem Reynolds numbers to enhance current knowledge about the flow resistance due to the vegetation arrays. In this context, the effect of vegetation density, flow conditions, and submergence ratio on the total flow resistance parameters and drag coefficient were evaluated systematically, and some empirical equations were proposed to estimate these resistance parameters. Furthermore, some of the experimental cases were investigated by a numerical study based on detached eddy simulation. The numerical analyses provided to evaluate bed shear stresses on the drag plate so that equations were derived to calculate the contribution of bed friction to the total flow resistance. It was observed that there was a strong consistency between the experimentally and numerically found drag coefficients. Finally, flow characteristics and structures in the vegetation arrays were examined by numerical analyses.

Subject Keywords

Open channel flow, Submerged and emergent vegetation array, Flow resistance and characteristics, Drag coefficient, Computational Fluid Dynamics

URI

https://hdl.handle.net/11511/101337

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

E. Haspolat, “EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE EFFECT OF A VEGETATION ARRAY TO THE FLOW RESISTANCE AND CHARACTERISTICS,” Ph.D. - Doctoral Program, Middle East Technical University, 2022.