User Forum of Software BASEMENT

qtheiler

User

Registered: 2015-07-30

Posts: 60

Sluice gate with sediment transport

Hi Everybyody,

I'm building a model with a sluice gate. This gate will represent the effect of a bridge. I have used an Inner boundary to define this bridge. My initial condition is shown at the link below:

https://www.dropbox.com/s/vsv1khgiv608k … 5.png?dl=0

Fist Question: to define the initial condition, compare to the bottom, if the 2 cross sections are not at the same elevation, what would be the best choice for the gate bottom level (a1or a2)? I suggest to use a1 as it is the lowest area. Do you think that's a good idea? I'v seen that if the gate bottom level is a2 it will create an error because the bottom of XS1 is higher than this bottom level a2. Does it have sense for you?

Second question: If a define the gate bottom level a1, how would it works if there is erosion? I mean, if the bottom is loweer than the gate bottom level, the potential area for the flux would be the purple area or the blue area (in case of the choice of a1)? The gate bottom level would it take into acount the bottom that is moving? In case of erosion, would be the bottom gate moving with the bottom?

Thank you very much for your help,

Cheers,

Quentin

sajjad

User

Registered: 2014-10-01

Posts: 101

Re: Sluice gate with sediment transport

Hi,

In v 2.7 (basechain) u have to explicitly declare the 'gate bottom level' if u do not do so basement does not work, so, it is your choice. Pl make a search with 'gate' u can get hold of a previous discussion on the subject of gate in 1d basement.
As far as erosion is concerned, hydraulic structures are costly structures, u build them strong by concreting and not vulnerable to failure, so make them immune from erosion by declaring 'fixed_bed' at the point where they r located.

Last edited by sajjad (2017-03-18 02:52:05)

qtheiler

User

Registered: 2015-07-30

Posts: 60

Re: Sluice gate with sediment transport

Hi,

Thank's for your advice. The problem is that actually, the bottom is not a fixed bed and I would like to study how deep could be the erosion. Any idea?

Cheers,

sajjad

User

Registered: 2014-10-01

Posts: 101

Re: Sluice gate with sediment transport

Use scour depth formulas from any Handbook on Hydraulics. They are likely to be more conservative than a cfd computation but they err on the side of safety. By computations, u may not get a calculation such as yours to converge due to numerical difficulties. The literature tells us about contraction scour, local scour etc. In your case it is contraction scour. You can investigate it by a faithful representation including gate (which might be numerically difficult to make converge) or by introducing a channel reduced width section without gate and then calculating. Regards

qtheiler

User

Registered: 2015-07-30

Posts: 60

Re: Sluice gate with sediment transport

Thanks for your advice. I will check this. Regards