Modeling of Developed Meanders of an Alluvial Channel

Yilmaz, Levent

doi:10.5772/15095

Cited by 2 publications

(3 citation statements)

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“…The first bend is a short entrance channel used as an initial upstream disturbance to develop patterns of the meander. This initial bend was formed at an angle of ( ) to the longitudinal axis of the flume; this procedure has been used by most researchers [4,5,13]. So it was extensively proved by pioneer researchers in achieving the meandering processes.…”

Section: Experiments Setup and Measurement Methodsmentioning

confidence: 99%

“…In which (k=1, 2,…, N) represents a sediment size class; and N is the total number of size classes; h is the local water level; u and v are the depth-integrated velocity components in the x and y directions respectively; C k is the depth-averaged suspended-load concentration of the k-th size class; C *k is the suspended-load transport capacity or the depth-averaged suspended-load concentration at the equilibrium state; is the turbulence diffusivity coefficient of sediment, determined with , in which is the turbulent Schmidt number, usually having a value between 0.5 and 1.0, is the settling velocity of sediment; α is the non-equilibrium adaptation factor having a value of 0.5, and and are the dispersion terms to account for the effect of the nonuniform distributions of flow velocity and sediment concentration [17]. The bed-load transport is determined by; (5) Where, C bk is the average concentration of bed load at the bed-load zone; q bk is the bed-load transport rate of size class k ; L t is the adaptation length for bed load ; q b*k is the corresponding bed-load transport capacity or bed-load transport rate at the equilibrium state; and and are the direction cosine components of bed load movement, which is assumed to be along the direction of bed shear. In case of meanders, α bx and α by are corrected to consider the effects of helical motions.…”

Section: Cche2d Modelmentioning

confidence: 99%

“…Erosion usually occurs on the outer banks (concave side) of the channel bends, while deposition takes place on the inner banks (convex side). The formation of riffles, and point bar-pool zones are considered as an essential characteristic of alluvial meandering channels, with pools placed at the apex of meander bends (outer bank), point bar located at (inner bank), and riffles placed at crossings between bends [4,5]. The complete hydraulic and morphologic changes of meander evolution can record by the numerical model spatially and temporally.…”

Section: Introductionmentioning

confidence: 99%

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2D Model to Investigate the Morphological and Hydraulic Changes of Meanders

Maatooq

Hameed

2020

ETJ

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River engineering investigations require some level of hydrodynamic and morphologic analysis. The detailed of the hydraulic and morphologic features through meander evolution can be recorded by the numerical model spatially and temporally. The Center for Computational Hydro-science and Engineering, two- dimensional model (CCHE2D V3.29) was adopted to investigate the hydraulic and morphologic changes through meander’s evolution. Through the experimental work, a series of experiments runs were carried out through combining different geometric and hydraulic parameters to produce different experiment conditions. These parameters are flow rate, bed slope, and different initial incised and wide channels for both rectangular and trapezoidal sections. The CCHE2D model was calibrated and verified using two sets of experimental data. According to the computed values of statistical indicators, BIAS, NSE, and MAE of 0.0084, 0.96, and 0.0132 respectively for water level simulation, and 0.007,0.94, and 0.0182 respectively for bed level simulation, the calibrated Manning’s roughness which gives an acceptable agreement between simulated and measured water and bed levels was 0.029. The verification results were evaluated by the same statistical indicators of BIAS, NSE, and MAE of 0.09, 0.81, and 0.018, respectively, as evidenced by the statistical indicators, values that the CCHE2D model was reasonably capable of simulating the hydraulic and morphological changes through meander evolution.

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Section: Experiments Setup and Measurement Methodsmentioning

confidence: 99%

Section: Cche2d Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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