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Problem in Sediment Transport with Discharge Input Only in Flow
Bilge Karakutuk, modified 2 Years ago.
Problem in Sediment Transport with Discharge Input Only in Flow
Youngling Post: 1 Join Date: 5/17/23 Recent Posts
Dear Delft3D Community,
I am currently working on Delft3D-FLOW, utilizing a 3D model to observe sediment transport under different discharge conditions. While the simulation itself concludes without any errors or warnings, the results are not in line with expectations. Despite the velocity distribution appearing reasonable across the intake and discharge locations, some suspended sediment transport results in too far areas which are illogical, and cumulative erosion/deposition distribution is not calculated, seeming like an instability problem??
In FLOW, my model has 10 layers vertically, where the layer thickness decreases from top to bottom (bed layer). I have specified each intake section in 15 grid cells (5 horizontal*3 vertical) and the discharge section in 35 grid cells (5 horizontal*7 vertical). These discharge grids are specified for the 2nd, 3rd, and 4th layers from the top. For each grid of intakes, the flow is determined as -5.55 m3/s with no additional sediment fraction and for each grid of the discharge, the flow is determined as 9.52 m3/s with no additional sediment fraction. Only sand (as a non-cohesive sediment) has been considered through the simulation process, where the simulation duration is 12 hours and the time step is 0.1 min. The only input is the negative (pumping) discharge and the positive discharge where each of the discharge types is defined as “Normal” and the interpolation method is chosen as “Linear”.
The simulation results are expectable in terms of water level and velocity but there is suspended sediment transport in too far areas from the input (discharge) locations where expected transport does not appear near the input area. The cumulative erosion/sedimentation results are also all zero.
Do you have any experience or ideas related to such a problem?
Consequently, I suspect that the issue may stem from the specified discharges; however, I am unable to comprehend why the sediment transport fails to correlate with the observed velocity behavior. Could you provide insights into the possible reasons behind this problem?
With best regards,
I am currently working on Delft3D-FLOW, utilizing a 3D model to observe sediment transport under different discharge conditions. While the simulation itself concludes without any errors or warnings, the results are not in line with expectations. Despite the velocity distribution appearing reasonable across the intake and discharge locations, some suspended sediment transport results in too far areas which are illogical, and cumulative erosion/deposition distribution is not calculated, seeming like an instability problem??
In FLOW, my model has 10 layers vertically, where the layer thickness decreases from top to bottom (bed layer). I have specified each intake section in 15 grid cells (5 horizontal*3 vertical) and the discharge section in 35 grid cells (5 horizontal*7 vertical). These discharge grids are specified for the 2nd, 3rd, and 4th layers from the top. For each grid of intakes, the flow is determined as -5.55 m3/s with no additional sediment fraction and for each grid of the discharge, the flow is determined as 9.52 m3/s with no additional sediment fraction. Only sand (as a non-cohesive sediment) has been considered through the simulation process, where the simulation duration is 12 hours and the time step is 0.1 min. The only input is the negative (pumping) discharge and the positive discharge where each of the discharge types is defined as “Normal” and the interpolation method is chosen as “Linear”.
The simulation results are expectable in terms of water level and velocity but there is suspended sediment transport in too far areas from the input (discharge) locations where expected transport does not appear near the input area. The cumulative erosion/sedimentation results are also all zero.
Do you have any experience or ideas related to such a problem?
Consequently, I suspect that the issue may stem from the specified discharges; however, I am unable to comprehend why the sediment transport fails to correlate with the observed velocity behavior. Could you provide insights into the possible reasons behind this problem?
With best regards,