Turbulent rectangular compound open channel flow study using multi-zonal approach

Abstract

In this paper, an improved Shiono-Knight model (SKM) has been proposed to calculate the rectangular compound open channel flows by considering a multi-zonal (MZ) approach in modelling turbulence and secondary flows across lateral flow direction. This is an effort to represent natural flows with compound shape more closely. The proposed model improves the estimation of secondary flow by original SKM model to increase the accuracy of depthaveraged velocity profile solution formed within the transitional region between different sections (i.e. between main-channel and floodplain) of compound channel. This proposed MZ model works by sectioning intermediate zones between floodplain and main-channel for running computation in order to improve the modelling accuracy. The modelling results have been validated using the experimental data by national UK Flood Channel Facility. It has been proven to work reasonably well to model secondary flows within the investigated compound channel flow cases and hence produce better representation to their flow lateral velocity profile.

Anisotropy in the Free Stream Region of Turbulent Flows through Emergent Rigid Vegetation on Rough Beds

“…Recent researches showed that different rectangular and trapezoidal shapes as well as the corner angles can exert a strong impact on the flow velocity distribution and its induced secondary flow [33][34][35]; hence, they may affect the sediment transport process [36]. Therefore, new analytical models of sidewall turbulence effect on streamwise velocity profile have been recently proposed (e.g., [35,37]) for uneven narrow and wide channels. These analytical models could be improved by considering extra turbulence zones represented by both vegetation and rough beds.…”

Velocity Profile and Turbulence Structure Measurement Corrections for Sediment Transport-Induced Water-Worked Bed

“…The above-mentioned problem can occur due to misaligned measurements as schematically described by Figure 1, especially in natural channel flows which subject to changing channel characteristics, including irregular side-wall and width conditions [5,6]. In Figure 1, the discrepancy of the measured and intended streamwise flow profiles can result from the bed orientation that displaces the actual measured line from the expected measured line.…”

Sediment Deposition within Rainwater: Case Study Comparison of Four Different Sites in Ikorodu, Nigeria

“…They can exist in the form of clay to coarse sand under different flow and atmospheric conditions, as extensively studied in various literature [1][2][3][4][5]. In natural and man-made terrains, the sediment transportation can be significant, and its sources are complex and varied [6][7][8]. This further complicates the effort to retain clean water for consumption or other usages.…”

“…These atmospheric sediment depositions may be further influenced by different local environmental features. Such features can include land use activities, the soil texture, wind speed, vegetation, vegetative residue, surface roughness, particle aggregate size distribution, soil moisture and rainfall [7,21]. In this study, a set of experiments were conducted to determine the characteristics of sediment matter from the atmosphere that settles in the stored rainwater.…”