Project Details

Abstract

Flow through transition of bed roughness occurs in many situations in highway transportation including culverts, bridge abutments, and roadways in the floodplain, where the bed materials can change abruptly from one type to another. A sudden change in bed roughness also occurs frequently in the laboratory when soil erosion and scour is studied using a sediment recess in an open-channel flume. In all the above, the bed shear stress is a fundamental flow parameter that must be determined accurately.

A research project is proposed to investigate the use of logarithmic law (log law) for finding bed shear stress near a sudden change in bed roughness. Velocity field measurements will be obtained using a Particle Image Velocimetry (PIV) system. The measured data will be used to determine the distribution of bed shear stress by control volume analysis using the linear momentum equation to determine whether the log law can be applied to a developing boundary layer downstream of a bed roughness transition and develop procedures to reduce the measurement uncertainty of the method.

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