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How to improve the lateral propagation of scour hole (3D)

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Old   April 18, 2014, 00:38
Default How to improve the lateral propagation of scour hole (3D)
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Sugonghak PC Bang
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Hi,

I have tried to performed the 3D lateral propagation of pipeline. I have obtain a small scour hole after 300s of run time. However, the desired result should be that the scour extend until the end of the pipe. This does not occur as the scour hole maintain at the same scour length regardless of changes to any parameter (drag coefficient, velocity, sediment size,etc).

My speculation is that the FLOW-3D code which is designed for equilibrium state has to be changed into non-equilibrium equation so that the scour hole will continue to propagate. But, I dont know how to change even though i have come across some paper regarding customization of FLOW-3D code.

Please advise if you have any idea. Thanks alot!
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Last edited by sycst911; April 20, 2014 at 23:04.
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Old   April 28, 2014, 14:06
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Jeff Burnham
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The developers at Flow Science have re-written the scour module in the upcoming v11. Older versions are maybe not so good with multiple species armoring, so you should try to use only one species. Also make sure you set the Critical Shields Parameter yourself: the auto-equation is not good for all sizes. Also try changing the Critical Shields Parameter a lot and see if there are changes in the results: the pre-v11 scour models are very cell-size sensitive, so Shields Parameter must be a "knob" to control the scour, and not a real value. v11 will have better resolution of the bed/water interface, so Shields Parameter will be more physical in that version.
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Old   April 29, 2014, 22:07
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Quote:
Originally Posted by JBurnham View Post
The developers at Flow Science have re-written the scour module in the upcoming v11. Older versions are maybe not so good with multiple species armoring, so you should try to use only one species. Also make sure you set the Critical Shields Parameter yourself: the auto-equation is not good for all sizes. Also try changing the Critical Shields Parameter a lot and see if there are changes in the results: the pre-v11 scour models are very cell-size sensitive, so Shields Parameter must be a "knob" to control the scour, and not a real value. v11 will have better resolution of the bed/water interface, so Shields Parameter will be more physical in that version.
Thanks JBurnham for the reply.

Yes, but in my case, i have tried with only one species. Still, the result isn't favorable. The scour does not propagate as desired.

I have also tried to manipulate the shields parameter,drag coefficient, bedload coefficient, etc..Even changing the particle size and flow velocity, the scour does not propagate to the end of the pipeline.

I wonder if this is the limitation of FLOW3D software?
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