scholarly journals Investigating the Effect of Relative Width on Momentum Transfer between Main Channel and Floodplain in Rough Rectangular Compound Channel Sunder Varius Relative Depth Condition

2016 ◽  
Vol 06 (04) ◽  
pp. 225-231 ◽  
Author(s):  
Shima Bahadori ◽  
Mehdi Behdarvandi Askar
Keyword(s):  
Momentum Transfer ◽  
Main Channel ◽  
Relative Depth ◽  
Relative Width ◽  
Compound Channel ◽  
Depth Condition

scholarly journals Simulations of Depth-Averaged Streamwise Velocity of Meandering Compound Channel using TELEMAC Modules

2018 ◽  
Vol 65 ◽  
pp. 07001
Author(s):  
Abdul Haslim Abdul Shukor Lim ◽  
Zulhilmi Ismai ◽  
Mohamad Hidayat Jama ◽  
Md. Ridzuan Makhtar
Keyword(s):  
Stokes Equations ◽  
Computing Time ◽  
Streamwise Velocity ◽  
Main Channel ◽  
Navier Stokes ◽  
Relative Depth ◽  
Compound Channel ◽  
Navier Stokes Equations ◽  
Numerical Tools ◽  
Good Agreement

Capabilities of numerical tools to simulate fluid problems significantly depend on its methods to solve for the Navier-Stokes equations. Different dimensional computing tools using the same horizontal meshes were used to simulate flow conditions inside non- and vegetation meandering compound channel. Both tools give good agreement for simulations of depth-averaged streamwise velocity inside the main channel, but its capabilities vary significantly for simulations on floodplains. Lower relative depth recorded a higher percentage of errors than flow with higher relative depth. Vegetation along the main channel increased the flows complexity especially in the area near the vegetation thus reducing the simulation capabilities of the computing tools. Simulations work by TELEMAC-3D significantly better in the areas with highly dimensional and turbulence conditions. TELEMAC-2D is still useful because of its simplicity and lower computing time and resources required.

scholarly journals Prediction of Boundary Shear Stress Distribution in Converging Compound Channel Using Gene Expression Programming

2022 ◽  
Author(s):  
Bandita Naik ◽  
Vijay Kaushik ◽  
Munendra Kumar
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Shear Force ◽  
Gene Expression Programming ◽  
Main Channel ◽  
Shear Stress Distribution ◽  
Force Distribution ◽  
Compound Channel ◽  
Boundary Shear ◽  
Boundary Shear Stress

Abstract The computation of the boundary shear stress distribution in an open channel flow is required for a variety of applications, including the flow resistance relationship and the construction of stable channels. The river breaches the main channel and spills across the floodplain during overbank flow conditions on both sides. Due to the momentum shift between the primary channel and adjacent floodplains, the flow structure in such compound channels becomes complicated. This has a profound impact on the shear stress distribution in the floodplain and main channel subsections. In addition, agriculture and development activities have occurred in floodplain parts of a river system. As a consequence, the geometry of the floodplain changes over the length of the flow, resulting in a converging compound channel. Traditional formulas, which rely heavily on empirical approaches, are ineffective in predicting shear force distribution with high precision. As a result, innovative and precise approaches are still in great demand. The boundary shear force carried by floodplains is estimated by gene expression programming (GEP) in this paper. In terms of non-dimensional geometric and flow variables, a novel equation is constructed to forecast boundary shear force distribution. The proposed GEP-based method is found to be best when compared to conventional methods. The findings indicate that the predicted percentage shear force carried by floodplains determined using GEP is in good agreement with the experimental data compared to the conventional formulas (R2 = 0.96 and RMSE = 3.395 for the training data and R2 = 0.95 and RMSE = 4.022 for the testing data).

Morphological effects of a hydraulic lifting dam on the middle Fenhe River, China

2021 ◽  
Author(s):  
Yufang Ni ◽  
Zhixian Cao ◽  
Wenjun Qi ◽  
Xiangbin Chai ◽  
Aili Zhao
Keyword(s):  
Shallow Water ◽  
General Pattern ◽  
Water Storage ◽  
Main Channel ◽  
Environmental Restoration ◽  
Two Dimensional ◽  
Compound Channel ◽  
Computationally Efficient ◽  
Bed Deformation ◽  
Numerical Predictions

<p>Hydraulic lifting dams become increasingly popular in China for water storage, river landscaping and environmental restoration. Inevitably, dams influence riverine morphology. Unfortunately, current understanding of this topic has remained rather limited. Here, the morphological effects of a hydraulic lifting dam on the middle Fenhe River, China are investigated. This reach features a compound channel and floodplains, and the riverbed is mainly composed of silt that can be easily eroded, indicating potential significant bed deformation. A computationally efficient depth-averaged two-dimensional shallow water hydro-sediment-morphodynamic model is employed. Unstructured meshes are refined around dam structures to accurately present topography. The numerical predictions show discrepancies of morphological responses of the main channel and floodplains to different operation schemes of the hydraulic lifting dam. This work helps to support decisions on the management of hydraulic lifting dams on the middle Fenhe River and reveals a general pattern for the morphological impact of hydraulic lifting dam.</p>

scholarly journals 3-D Flood Flow Structures in a Doubly Meandering Compound Channel under Dominant Relative Depth

2008 ◽  
Vol 11 ◽  
pp. 735-743
Author(s):  
G. M. Tarekul Islam ◽  
Yoshihisa Kawahara ◽  
Nobuyuki Tamai
Keyword(s):  
Flow Structures ◽  
Relative Depth ◽  
Compound Channel ◽  
Flood Flow

scholarly journals An analytical solution for flow estimation of a meandering compound channel

2018 ◽  
Vol 40 ◽  
pp. 06043
Author(s):  
Arpan Pradhan ◽  
Kishanjit Kumar Khatua
Keyword(s):  
Momentum Transfer ◽  
Analytical Model ◽  
Force Balance ◽  
Channel Cross Section ◽  
Small Scale ◽  
Data Sets ◽  
Compound Channel ◽  
Mean Velocity ◽  
Dimensional Parameter ◽  
Flow Estimation

An analytical model is proposed to determine the discharge capacity in a meandering compound channel. The channel cross-section is divided into four sub-sections, such as the lower main channel, the floodplain within the meander belt and the two outer floodplains. Momentum transfer in-between these four subsections is taken into consideration in the analytical model. The model basically determines the force balance of each individual subsection to predict its mean velocity and thereby the sub-sectional discharge. The paper suggests a non-dimensional parameter, αT, which is the momentum transfer coefficient, that is determined to be unique for each individual channel. The paper deals with the calibration of this parameter for both largescale and small-scale data sets.

scholarly journals Effects of Floodplain Vegetation on Momentum Transfer in Compound Channel

2011 ◽  
Vol 67 (2) ◽  
pp. I_549-I_557 ◽  
Author(s):  
Fumiaki HASEGAWA ◽  
Takuya YAMAMOTO ◽  
Fatima JAHRA ◽  
Yoshihisa KAWAHARA
Keyword(s):  
Momentum Transfer ◽  
Compound Channel ◽  
Floodplain Vegetation
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