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How to stabilize hydrograph outflow of a storage

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Old   January 17, 2015, 06:18
Default How to stabilize hydrograph outflow of a storage
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RoyDaniel
Join Date: Oct 2014
Location: Taiwan
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Dear All Flow 3D Experts,

How are you ? I am hope you are all great in early early start of this new year 2015. I just want to share what I am doing now on Flow 3D modelling. I am trying to creating Storage routing model now. Itís just a simple long rectangular storage with hydrograph inflow in Xmin with peak as much as 6000 cms (please see figure 1a&b Storage). The aim of the model is to see Inflow-Outflow hydrograph like in attachment figure 2 InflowOutflowHydrograph. But when I see from the result at the early second until 8000 second, the hydrograph shows very unstable result. It oscillates so high (please see figure 3, Result Flow 3D). And also following tables are another description about my model. Could any body help me how to smooth or stabilize the Outflow or Xmax hydrograph as shown in figure 3 Result Flow 3D?

Table of BC
Location BC Symbols Remark
Xmin Volume Rate VFr Hydrograph
Xmax Outflow P Hydrograph of (surface water level vs time) exactly at the weir
Ymin Wall W no water allowed to flow laterally
Ymax Wall W no water allowed to flow laterally
Zmin Wall W No water allowed to flow down
Zmax Pressured P Initially itís not pressurized flow

Table of Mesh Size
Direction Mesh Size (m)
deltaX 20
deltaY 25
deltaZ 10

Table Time step
Time Step Control Time step (sec)
Initial Time Step 1E-20
Maximum Time Step 1E-25


Thank you so much for your help

Best Regards,
Roy
Attached Images
File Type: jpg Figure 1a Storage.jpg (27.5 KB, 7 views)
File Type: jpg Figure1b Storage.jpg (34.1 KB, 7 views)
File Type: png Figure 2 InflowOutflow Hyd.png (8.8 KB, 7 views)
File Type: jpg Figure 3 Result flow 3D.jpg (23.9 KB, 7 views)
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flow 3d, hydraulic structures, open channel flow, reservoir

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