This thesis present results relating to a series of laboratory experiments investigating the velocity field in order to provide an understanding into the flow structures by describing the mechanisms and transport features of heterogeneous (patchy) flexible and rigid strip vegetation flow interaction with gravel roughness which could be used to understand sediment transport in the future. The experimental results were examined in a context of shear layer arising as a result of flexible and rigid vegetation patchy roughness distribution with gravel roughness. It is shown that relative to a gravel bed, the vegetated section of the channel generally resembles a free shear layer. The resistance within the vegetation porous layer reduces the velocity and creates a transition of high velocity flow across the interface at the top of vegetation; of primary importance is the shear layer at the top of vegetation and roughness boundary regions which are shown to influence and dominate the overall momentum transport. These results have been used to calibrate a numerical model for the depth-averaged streamwise and boundary shear stress distribution using the Shiono and Knight Method (SKM). The model demonstrated approximately 90% accuracy in depth-averaged streamwise velocity distribution in comparison with the experimental data.ud
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