introduction: due to sensitiveness of flow to roughness coefficient (rc), selection of this coefficient is important in earth canals designing purposes. precision selection of this coefficient is necessary for design and operation of earthen canals purposes. overestimation of the actual amount of this coefficient will cause an underestimation for flow velocity. accordingly, sedimentation in the...

the manning roughness coefficient is an important parameter in the design and evaluation of furrow irrigation. despite its importance, estimation of this parameter for surface irrigation is very difficult, particularly in furrow irrigation. in this study, an evalue model was used to estimate the manning roughness coefficient in furrow irrigation. the model was based on volume balance and develo...

abstract in all river engineering projects, determination of flow resistance is essential. most commonly, the manning roughness coefficient, , is used to describe the flow resistance or relative roughness of main channel or flood plane. over the past decades little or no study has been conducted to investigate the effects of particle shapes on manning roughness coefficient. therefore, it is the...

the influence of surface roughness magnitude and direction on dry static friction coefficient between two similar steel samples has been studied through an experiment. a testing apparatus has been designed and fabricated to measure the friction coefficient for a few forms of surface asperity. according to the results of the experiments, dry friction coefficient is affected by both magnitude and...

there are different methods for controling the flood damages which one of them is flood zoning. in this method, flood zones are determined by simulating river hydraulic behavior and its flood plain for different return periods.in other hand, soil and specially plant coverage are the most effective factor to determine manning roughness coefficient. so it is expected, seasonal plant coverage chan...

Three synchronized pulsed Doppler wind lidars were deployed from May 2016 to June 2016 on the shores of a wide Norwegian fjord called Bjørnafjord to study the wind characteristics at the proposed location of a planned bridge. The purpose was to investigate the potential of using lidars to gather information on turbulence characteristics in the middle of a wide fjord. The study includes the anal...

Surface texturing is used to increase hydrodynamic pressure and reduce friction and wear between parallel sliding surfaces in a variety of applications. The shape, geometry, and density of the patterned microtexture features play a key role in the tribological performance of such textured slider bearings. Lubrication models are used to predict the load-carrying capacity, friction coefficient, a...

The article presents the results of improving numerical method developed in [1-3] for calculating roughness coefficient riverbed (RCOTR) to increase stability and using it study dependence RCOTR Instruch River on dimensionless complexes different seasons.