scholarly journals ANALISIS SEDIMENTASI LAGUNA SEGARA ANAKAN DENGAN PEMODELAN NUMERIK ANGKUTAN SEDIMEN KOHESIF

2021 ◽  
Vol 12 (1) ◽  
pp. 1-14
Author(s):  
Irham Adrie Hakiki ◽  
Leo Eliasta Sembiring ◽  
Cahyo Nur Rahmat Nugroho
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Transport Model ◽  
Factor Model ◽  
Cohesive Sediment ◽  
Analysis Model ◽  
Sediment Volume ◽  
Cohesive Sediment Transport ◽  
Speed Up ◽  
One Year

Sagara Anakan Lagoon has been continuously receded caused by the high sedimentation rate. The deposited sediment volume was predicted to be around 1 million m3/year. This phenomenon, if not treated will harm the existing ecosystem and also could cause many kinds of its native biota extinct. Engineering could be applied to prevent it. However, the transport and sedimentation pattern must be known for it to be effective.  Silting in Sagara Anakan Lagoon simulated by using MIKE21 numerical model which could simulate sediment transport in 2D horizontal scheme. The deposited sediment, mainly consisted of mud, so the model must be capable for simulating cohesive sediment transport. Model is set to simulate one year of morphological event which reached with the usage of time speed up acceleration factor. Model calibrated to be able to simulate a deposition event in the order of one million m3/year. Model calibrated by tuning critical bed shear stress for deposition   and erosion  parameters as a base for sensitivity analysis. Model result shown that the sedimentation in Sagara Anakan Lagoon is caused by asymmetry of flood and ebb current. Major siltation happened around the delta with the maximum and mean observed bed change are approximately 0.6 m and 0.16 m respectively. The setup for this model could be used as a base model for planning an engineering approach for controlling sediment in Sagara Anakan Lagoon.Keywords: Numerical model, cohesive sediment, mud transport, estuary modellingKata Kunci: Model numerik, sedimen kohesif, transpor lumpur, pemodelan estuari

scholarly journals A Methodology for Estimating the Parameters in Three-Dimensional Cohesive Sediment Transport Models by Assimilating In Situ Observations with the Adjoint Method

2017 ◽  
Vol 34 (7) ◽  
pp. 1469-1482 ◽  
Author(s):  
Daosheng Wang ◽  
Jicai Zhang ◽  
Ya Ping Wang ◽  
Xianqing Lv ◽  
Yang Yang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Adjoint Method ◽  
Settling Velocity ◽  
Transport Model ◽  
Three Dimensional ◽  
Temporal Variations ◽  
Cohesive Sediment ◽  
Cohesive Sediment Transport ◽  
Resuspension Rate

AbstractThe model parameters in the suspended cohesive sediment transport model are quite important for the accurate simulation of suspended sediment concentrations (SSCs). Based on a three-dimensional cohesive sediment transport model and its adjoint model, the in situ observed SSCs at four stations are assimilated to simulate the SSCs and to estimate the parameters in Hangzhou Bay in China. Numerical experimental results show that the adjoint method can efficiently improve the simulation results, which can benefit the prediction of SSCs. The time series of the modeled SSCs present a clear semidiurnal variation, in which the maximal SSCs occur during the flood tide and near the high water level due to the large current speeds. Sensitivity experiments prove that the estimated results of the settling velocity and resuspension rate, especially the temporal variations, are robust to the model settings. The temporal variations of the estimated settling velocity are negatively correlated with the tidal elevation. The main reason is that the mean size of the suspended sediments can be reduced during the flood tide, which consequently decreases the settling velocity according to Stokes’s law, and it is opposite in the ebb tide. The temporal variations of the estimated resuspension rate and the current speeds have a significantly positive correlation, which accords with the dynamics of the resuspension rate. The temporal variations of the settling velocity and resuspension rate are reasonable from the viewpoint of physics, indicating the adjoint method can be an effective tool for estimating the parameters in the sediment transport models.

scholarly journals MODELING ESTUARIAL COHESIVE SEDIMENT TRANSPORT

1984 ◽  
Vol 1 (19) ◽  
pp. 199
Author(s):  
E.J. Hayter ◽  
A.J. Mehta
Keyword(s):  
Sediment Transport ◽  
Transport Model ◽  
Cohesive Sediment ◽  
Transport Processes ◽  
Weighted Residual Method ◽  
Dispersive Transport ◽  
Time Step ◽  
Advection Dispersion ◽  
Cohesive Sediment Transport ◽  
Suspended Sediment Concentrations

Cohesive sediment related problems in estuaries include shoaling in navigable waterways and water pollution. A two-dimensional, depth averaged, finite element cohesive sediment transport model, CSTM-H, has been developed and may be used to assist in predicting the fate of sorbed pollutants and the frequency and quantity of dredging required to maintain navigable depths. Algorithms which describe the transport processes of redispersion, resuspenslon, dispersive transport, settling, deposition, bed formation and bed consolidation are incorporated in CSTM-H. The Galerkin weighted residual method is used to solve the advection-dispersion equation with appropriate source/sink terms at each time step for the nodal suspended sediment concentrations. The model yields stable and converging solutions. Verification was carried out against a series of erosion-deposition experiments in the laboratory using kaolinite and a natural mud as sediment. A model application under prototype conditions is described.

scholarly journals NUMERICAL SIMULATION OF COHESIVE SEDIMENT TRANSPORT IN JAKARTA BAY

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
I.M. Radjawane ◽  
F Riandini
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Tidal Current ◽  
River Discharge ◽  
Cohesive Sediment ◽  
Flood Tide ◽  
Offshore Area ◽  
Easterly Wind ◽  
Cohesive Sediment Transport ◽  
Current Circulation

The 3D-numerical model has been applied to simulate the current circulation and cohesive sediment transport in the Jakarta Bay, Indonesia. Sediment load comes from 3 river mouths i.e. Angke River, Karang River, and Ancol River. The model was simulated to analyze the effect of tidal current and river discharge. A constant westerly and easterly wind was used as input of the model to see the influence of monsoonal season. The numerical result showed that the tidal current flows from east to western part of the bay during ebb tide and vice versa during flood tide. The surface current circulation was dominantlyinfluenced by the tidal current comparated with the wind and river discharge effects. Hight turbidity level was found near the river mounths with the range of 50 to 100 mg per l. This high in the offshore area of the bay the sediment concentration decreases up to 10 mg per l. The movement of sediments followed the current circulations. During the flood tide, the sediment concentratation from the mounth of Angke River moved to the western part of the bay. Model simulated for increasing the river discharge into two times showed that the sediment distributed to the offshore direction two time longer compare with the normal debit. The transport of sediment from the Angke and Karang Rivers to the offshore area reached up to 6 km, while it just reached plus minus 2,5 km from the Ancol River. Keyword: Numerical model, Cohesive sediment, Effect of tidal current and river discharge.

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