engleski

Methods of Roughness Coefficient Determination in Natural Riverbeds

The roughness coefficient determination in natural river beds is based on the analysis of boundary layer development along the canal walls. The structure of the open canal can be very complex and changeable which results in different evaluation methods of determining the roughness coefficient n. A considerable number of measured valued for similar surface canal characteristics are analyzed in order to determine the roughness coefficient for the observed natural canal. The paper offers parameters which affect the roughness coefficient variability in beds. The roughness coefficient variability along the flow which depends on water level changes has been additionally described and graphically presented. The paper presents the vertical velocity profiles which are result of the aquatic vegetation. The paper offers review of the most represented methods of roughness coefficient evaluation used in practice, as well as numerous empiric methods based on the grading structure of the slopes and the bottom of the canal as well as methods based on measuring data.

Roughness coefficient ; boundary layer ; evaluation methods ; vertical velocity

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