scholarly journals ANALISIS DISTRIBUSI KECEPATAN DAN SEDIMEN PADA TIKUNGAN 55° SALURAN TERBUKA TAMPANG SEGI EMPAT

2018 ◽  
Author(s):  
Ady Purnama
Keyword(s):  
Sediment Transport ◽  
Water Distribution ◽  
Measurement Data ◽  
Sediment Concentration ◽  
Base Line ◽  
Sediment Suspension ◽  
Channel Bend ◽  
Outer Bank ◽  
Velocity Flow ◽  
Acceleration And Deceleration

Predicting the behavior of the flow in the channel bend quite important, because the channel bend a fairly high degree of cartilage against the destructive force of water when compared to a straight channel. Phenomena that may occur and cause detriment is the phenomenon of sediment transport that passes through the channel bend. The phenomenon that occurs in the channel bend can be detected by measuring the field directly. For a case study of the Irrigation Mataram, research done by the measurement of the concentration profiles of sediment transport using devices Opcon. The study was conducted at a locations with the curves that have angles, α = 55° with Radius = 50 m. From the analysis of the measurement of velocity flow and sediment concentration suspensions were performed at the curves that have angles, α = 55° with Radius = 50 m, indicating that the minimum velocity for trend occurs near the base and the increase in size towards the surface of the stream. Flow velocity acceleration and deceleration experienced when through the turn, which increases the velocity flow in the bend side (inner bank) when passing the initial curves and velocity decreases as it passes through the opposite end of the turn and descent speed on the outside of the bend (outer bank) when passing through curves and initial experience increase in the inside of the turn as it passes through the end of the turn. The concentration of sediment suspensions have almost the same trend for the entire face, the concentration of sediment suspension increases towards the base line and decreased with the trend towards the surface of the water distribution more upright with a more uniform rate towards the surface of the water. In the transverse direction, the concentration of sediment suspension tends to increase towards the inner side of the bend when passing through the initial turn, and then decreases towards the inner side of the bend as it passes through the middle of the turn and increased again towards the inside of the turn as it passes through the final turn which resulted in deposition on the inside of the turn (inner bank) and erosion on the outside of the bend (outer bank) at the base of the channel. For analysis of the consentration of sediment suspension field measurement results are compared with the analysis of the Rouse equation and equation-Sugimoto Tanaka showed that the measurement data can reasonably predict the consentration of sediment suspension on curves, although the angle and bend radius varies. Measurement data of suspended sediment consentration approaching the value of data analysis results Rouse and Tanaka-Sugimoto.

scholarly journals KONSENTRASI SEDIMEN SUSPENSI PADA BELOKAN 57° SALURAN TERBUKA

2018 ◽  
Author(s):  
Ady Purnama
Keyword(s):  
Measurement Data ◽  
Concentration Field ◽  
Sediment Concentration ◽  
Outer Side ◽  
Base Line ◽  
Sediment Suspension ◽  
Straight Line ◽  
Data Value ◽  
Measurement Results ◽  
High Level

Predicting the behavior of the flow in the channel turned quite important, because the channel has turned a fairly high level prone to water damage when compared with the straight line. A phenomenon that often occurs and causes kerugikan in turn channel is the sediment transport phenomena.The phenomenon that occurs in the channel turn can be detected by performing measurements directly in the field. For a case study of parent channel mataram, the research done by measurement of sediment concentration profiles using the tool opcon suspension. The study was conducted on curves that have the angle, α = 57 ° with r = 50 m. From the analysis of the measurements of the concentration of sediment suspensions carried out in an open channel with a bend 57 °, indicating that the concentration of sediment suspension had a trend which is almost equal to the entire face, ie the concentration of sediment suspension is increased toward the base line and decreasing toward the surface of the water with the trend of distribution more upright with values more uniform towards the water surface. In the transverse direction, the concentration of sediment suspension tends to increase toward the inside of the bend when passing through the initial turn, then decreases towards the inside of the bend as it passes through the middle of the turn, and again increased toward the inside of the bend as it passes through the final turn which resulted in the deposition on the inside of the turn ( inner bank) and erosion on the outer side of the bend (outer bank) on the basis of the channel. For the analysis of sediment suspension concentration field measurement results are compared with the analysis of the rouse equation and the equation tanaka-sugimoto show that enough measurement data can predict sediment concentration suspension on curves, although the angle and radius of the bend is varied. Suspension of sediment measurement data value is closer to the data analysis results rouse and tanaka-sugimoto. The results of the analysis of tanaka-sugimoto could provide better results than analysis rouse.

scholarly journals Investigation of Shear Stress Distribution in a 90 Degree Channel Bend

2019 ◽  
Vol 24 (1) ◽  
pp. 213-220
Author(s):  
Seung Kyu Lee ◽  
Truong An Dang ◽  
Van Tuan Le
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
River Flow ◽  
Morphological Changes ◽  
Measurement Data ◽  
Shear Stress Distribution ◽  
Doppler Velocity ◽  
Channel Bend ◽  
Outer Bank ◽  
Maximum Value

Abstract Shear stress is a key parameter that plays an important role in sediment transport mechanisms; therefore, understanding shear stress distribution in rivers, and especially in river bends, is necessary to predict erosion, deposition mechanisms and lateral channel migration. The aim of this study is to analyze the shear stress distribution near a river bed at 90-degree channel bend using a depth-average method based on experimental measurement data. Bed shear stress distribution is calculated using the depth-averaged method based on velocity components data has been collected from a 3D-ADV device (three-dimensional acoustic doppler velocity) at different locations of a meandering channel. Laboratory experiments have been made at the hydraulic laboratory of the RCRFIDF (Research Center for River Flow Impingement and Debris Flow), Gangneung-Wonju National University, South Korea to provide data for simulating the incipient motion of the riverbed materials and then predicting the river morphological changes in the curved rivers. The calculated results show that the maximum value of shear stress distribution near the riverbed in the different cross sections of the surveyed channel occurs in a 70-degree cross section and occurs near the outer bank. From the beginning of a 40-degree curved channel section, the maximum value of the shear stress occurs near the outer bank at the end of the channel.

scholarly journals Modeling Hydro-Dynamics in a Harbor Area in the Daishan Island, China

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 192 ◽  
Author(s):  
Yuting Li ◽  
Zhiyao Song ◽  
Guoqiang Peng ◽  
Xuwen Fang ◽  
Ruijie Li ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Flow Velocity ◽  
Suspended Sediment ◽  
Hydrodynamic Model ◽  
Transport Model ◽  
Measurement Data ◽  
Cross Flow ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
The Impact

This study presents an incorporation and application of a two-dimensional, unstructured-grid hydrodynamic model with a suspended sediment transport module in Daishan, China. The model is verified with field measurement data from 2017: water level, flow velocities and suspended sediment concentration (SSC). In the application on the Daishan, the performance of the hydrodynamic model has been satisfactorily validated against observed variations of available measurement stations. Coupled with the hydrodynamic model, a sediment transport model has been developed and tested. The simulations agreed quantitatively with the observations. The validated model was applied to the construction of breakwaters and docks under a different plan. The model can calculate the flow field and siltation situation under different breakwater settings. After we have analyzed the impact of existing breakwater layout schemes and sediment transport, a reasonable plan will be selected. The results show that the sea area near the north of Yanwo Shan and Dongken Shan has a large flow velocity exceeding 2.0 m/s and the flow velocity within the isobath of 5 m is small, within 0.6 m/s. According to the sediment calculation, the dock project is feasible. However, the designed width of the fairway should be increased to ensure the navigation safety of the ship according to variation characteristics of cross flow velocity in channel.

Sediment transport modifications induced by submerged artificial reef systems: a case study for the Gulf of Venice

2014 ◽  
Vol 43 (1) ◽  
Author(s):  
Davide Bonaldo ◽  
Alvise Benetazzo ◽  
Andrea Bergamasco ◽  
Francesco Falcieri ◽  
Sandro Carniel ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Coastal Zone Management ◽  
Artificial Reef ◽  
Sediment Concentration ◽  
Quantitative Information ◽  
Small Scale ◽  
Zone Management ◽  
Basin Scale ◽  
Scale Modelling ◽  
Maritime Spatial Planning

AbstractThe shallow, gently sloping, sandy-silty seabed of the Venetian coast (Italy) is studded by a number of outcropping rocky systems of different size encouraging the development of peculiar zoobenthic biocenoses with considerably higher biodiversity indexes compared to neighbouring areas. In order to protect and enhance the growth of settling communities, artificial monolithic reefs were deployed close to the most important formations, providing further nesting sites and mechanical hindrance to illegal trawl fishing.In this framework, a multi-step and multi-scale numerical modelling activity was carried out to predict the perturbations induced by the presence of artificial structures on sediment transport over the outcroppings and their implications on turbidity and water quality. After having characterized wave and current circulation climate at the sub-basin scale over a reference year, a set of small scale simulations was carried out to describe the effects of a single monolith under different geometries and hydrodynamic forcings, encompassing the conditions likely occurring at the study sites. A dedicated tool was then developed to compose the information contained in the small-scale database into realistic deployment configurations, and applied in four protected outcroppings identified as test sites. With reference to these cases, under current meteomarine climate the application highlighted a small and localised increase in suspended sediment concentration, suggesting that the implemented deployment strategy is not likely to produce harmful effects on turbidity close to the outcroppings.In a broader context, the activity is oriented at the tuning of a flexible instrument for supporting the decision-making process in benthic environments of outstanding environmental relevance, especially in the Integrated Coastal Zone Management or Maritime Spatial Planning applications. The dissemination of sub-basin scale modelling results via the THREDDS Data Server, together with an user-friendly software for composing single-monolith runs and a graphical interface for exploring the available data, significantly improves the quantitative information collection and sharing among scientists, stakeholders and policy-makers.

scholarly journals Suspened sediment concentration and sediment transport rate under asymmetric waves.

1990 ◽  
pp. 295-296
Author(s):  
Shunsuke IKEDA ◽  
Makoto IFUKU ◽  
Tadao KAKINUMA ◽  
Hiromitsu GOTOH
Keyword(s):  
Sediment Transport ◽  
Sediment Concentration ◽  
Transport Rate ◽  
Sediment Transport Rate

scholarly journals Numerical Investigation of Hydrodynamics and Cohesive Sediment Transport in Cua Lo and Cua Hoi Estuaries, Vietnam

2021 ◽  
Vol 9 (11) ◽  
pp. 1258
Author(s):  
Viet Thanh Nguyen ◽  
Minh Tuan Vu ◽  
Chi Zhang
Keyword(s):  
Sediment Transport ◽  
Great Influence ◽  
Wave Model ◽  
Sediment Concentration ◽  
Wave Climate ◽  
Cohesive Sediment ◽  
Wave Direction ◽  
The South ◽  
The North ◽  
Cohesive Sediment Transport

Two-dimensional models of large spatial domain including Cua Lo and Cua Hoi estuaries in Nghe An province, Vietnam, were established, calibrated, and verified with the observed data of tidal level, wave height, wave period, wave direction, and suspended sediment concentration. The model was then applied to investigate the hydrodynamics, cohesive sediment transport, and the morphodynamics feedbacks between two estuaries. Results reveal opposite patterns of nearshore currents affected by monsoons, which flow from the north to the south during the northeast (NE) monsoon and from the south to the north during the southeast (SE) monsoon. The spectral wave model results indicate that wave climate is the main control of the sediment transport in the study area. In the NE monsoon, sediment from Cua Lo port transported to the south generates the sand bar in the northern bank of the Cua Hoi estuary, while sediment from Cua Hoi cannot be carried to the Cua Lo estuary due to the presence of Hon Ngu Island and Lan Chau headland. As a result, the longshore sediment transport from the Cua Hoi estuary to the Cua Lo estuary is reduced and interrupted. The growth and degradation of the sand bars at the Cua Hoi estuary have a great influence on the stability of the navigation channel to Ben Thuy port as well as flood drainage of Lam River.

scholarly journals Numerical Simulation of Deep-Sea Sediment Transport Induced by a Dredge Experiment in the Northeastern Pacific Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Kaveh Purkiani ◽  
Benjamin Gillard ◽  
André Paul ◽  
Matthias Haeckel ◽  
Sabine Haalboom ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Pacific Ocean ◽  
Suspended Sediment ◽  
Deep Sea ◽  
Numerical Models ◽  
Sediment Concentration ◽  
Ocean Model ◽  
Small Scale ◽  
Plume Dispersion ◽  
Deep Sea Sediment

Predictability of the dispersion of sediment plumes induced by potential deep-sea mining activities is still very limited due to operational limitations on in-situ observations required for a thorough validation and calibration of numerical models. Here we report on a plume dispersion experiment carried out in the German license area for the exploration of polymetallic nodules in the northeastern tropical Pacific Ocean in 4,200 m water depth. The dispersion of a sediment plume induced by a small-scale dredge experiment in April 2019 was investigated numerically by employing a sediment transport module coupled to a high-resolution hydrodynamic regional ocean model. Various aspects including sediment characteristics and ocean hydrodynamics were examined to obtain the best statistical agreement between sensor-based observations and model results. Results show that the model is capable of reproducing suspended sediment concentration and redeposition patterns observed during the dredge experiment. Due to a strong southward current during the dredging, the model predicts no sediment deposition and plume dispersion north of the dredging tracks. The sediment redeposition thickness reaches up to 9 mm directly next to the dredging tracks and 0.07 mm in about 320 m away from the dredging center. The model results suggest that seabed topography and variable sediment release heights above the seafloor cause significant changes especially for the low sedimentation pattern in the far-field area. Near-bottom mixing is expected to strongly influence vertical transport of suspended sediment.

Estimating rill erosion and sediment transport processes along a saturated purple soil slope

2021 ◽  
Author(s):  
Han Zhen ◽  
Xiaoyan Chen ◽  
Yanhai Li ◽  
Shiqi Chen ◽  
Xiaojie Gu ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Sediment Concentration ◽  
Transport Processes ◽  
Purple Soil ◽  
Rill Erosion ◽  
Soil Slope ◽  
Sediment Transportation ◽  
Erosion Models ◽  
Increasing Trend ◽  
Soil Slopes

A plough pan with reduced permeability always accumulates infiltrated water along slopes then saturates the cultivated layer under continuous rain. Topsoil saturation is a frequent phenomenon and an important process of the special soil slopes. A methodology and device system was used in this study to keep cultivated purple soil saturated. Strands of scouring tests were developed to quantify the rill erosion and sediment transport processes along a saturated purple soil slope at four experiment slopes (5°, 10°, 15°, and 20°) and three flow discharges (2, 4 and 8 L min−1). The experimental results indicated that the sediment transport capacity on a saturated purple soil slope ranged from 0.03 to 1.56 kg s−1 m−1 with the increasing trend along the slope gradient and flow discharge, and the increasing trend could be well matched by a nonlinear multivariable equation. The sediment concentration of the saturated purple soil slope exponentially increased with rill length and decreased with the increment rate and the maximum sediment concentrations observed in this study in different hydraulic events ranged from 108.13 to 1174.20 kg m-3. Saturated and non-saturated purple soil slopes erode differently with the maximum sediment concentration of saturated purple soil slope recorded at approximately 1.42-2.10 times the values for non-saturated purple soil slope. The findings of this research help illustrate the sediment transportation and erosion behaviors of a saturated purple soil slope, and serve as the basis for determining the parameters in the erosion models of the purple soil slope.

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