UBC Theses and Dissertations
Scale models of gravel bed rivers Parent, Alain Paul
The combined studies of flow processes in a full size gravel-bed river and its associated small-scale model have demonstrated the applicability of the similitude concepts as well as the potential of scale models for quantitative research in fluvial geomor phology. This scaling investigation considered the comparison of velocity profiles, shear stress measurements, flow structure and surface bed material samples. An extension of the strict comparison on a detailed level of field and laboratory processes in a specific case consisted in the proposition of a "generic model" framework according to which laboratory systems are viewed as part of the same family as field ones if some crucial conditions are satisfied. The pool-riffle sequence, used as a vehicle for the demonstration herein, is presented as a poorly Known but ubiquitous river phenomenon which would benefit from such research methodology. The laboratory study performed herein revealed the need for an appraisal of the variability of shear stress estimates in intermediate relative roughness flows such as field size gravel-bed rivers. Knowledge of elements of the history of the prototype (field) river was also demonstrated to be important for the appraisal of model performance.
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