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Step spillway!

113 Views, 7 Replies
12/23/2017 10:09 AM

Help me understand what is the problem, I try to simulate in 2D stepped spillway. The initial data is very simple, the grid is quite thick. But in the initial stage there is a strong rise in the water level, as a result, the task loses its meaning.

The second question concerns what tools Autodesk CFD can simulate a similar mode of operation of the weir (the changing level of water in the reservoir zone)

Step spillway.cfz

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Message 1 of 7 ( Views: 113 )

Re: Step spillway!

12/23/2017 3:20 PM

Could I suggest you really do this in 2D? This is just a really thin 3D (which is usually worse than full 3D or 2D)...

I am sure we can do what you need, sometimes it takes a bit of thought to set it up though.


I suggest you go with 2D and a finer mesh, that ought to get things working better.


Hope that helps!


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Message 2 of 7 ( Views: 100 )

Re: Step spillway!

12/25/2017 3:42 AM

Thank you, I will try to perform a full 2D model, the smaller will be the fewer elements and the task will be solved more quickly.

But I really want to implement a calculation like the following example


So far, I have not found the right tools in Autodesk CFD, for a similar model

At the moment, I'm doing a model of a well of blanking, the screen and the source file are attached. The calculation is not over yet

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Message 3 of 7 ( Views: 92 )

Re: Step spillway!

12/25/2017 7:33 AM

I rebuilt the model of a stepped spillway in 2D, the result is just as unpredictable.
At the beginning of the calculation, everything looks normal, but it is worth the jump of the water from the first step, as in the initial section, a sharp rise in the water level begins, followed by a collapse.

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Message 4 of 7 ( Views: 83 )

Re: Step spillway!

12/27/2017 5:29 PM

Could you share a CFZ again? I can take a look tomorrow, which I hope is OK for you :)


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Message 5 of 7 ( Views: 62 )

Re: Step spillway!

01/04/2018 7:57 AM

I have reload cfz

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Message 6 of 7 ( Views: 50 )

Re: Step spillway!

01/04/2018 9:40 AM

Hi @beggar,


A few points on your model:


1. Your pressure and velocity BCs are touching this will cause huge numerical issues as CFD will apply an nonphysical discontinuity there!


2. Slip / symmetry BC doesn't seem physical on the spillway I would apply no BC to the ground such that it acts like a wall.


Here is a really helpful webinar on free surface flows in which Marwan goes through an example which resembles your problem.


All the best,


David Short
Technical Support Specialist, Simulation

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