2D links across rivers

[gmmorrison 0]

Hi

I'm having problems linking 2D domains in my model. I've constructed a model with a 30m grid which has four 10m grids nested within. It's a tidal area so the river levels fluctuate alot.

The links seem to be working fine except where they cross some of the rivers where I get strange flow patterns, originating from the edges of the water extent. I think its to do with the water levels at dry nodes being interpolated across causing an uneven water surface profile, as shown in the rough sketch attached. Is this what TUFLOW does?

So far I have tried altering the locations of the nodes (many times!) and changing the zpt values in the 10m domain along the boundary to equal the ZC value in the 30 m domain.

I'm now out of ideas and welcome any suggestions. I've also attached are the river cross sections for the two rivers causing problems, the Blackwater and the Colne, showing the node locations and the minimum water levels.

Thanks

gillian

water_interpolation.bmp

[cardno 0]

I would suggest varying the "d" value in the 2d_bc layer connecting the 2D domains. Start with the minimum value (30 metres in this case), then try some larger values, depending on how you have digitised the boundary.

[Bill Syme 0]

Hi Gillian

Have you tried using the .tcf command "Link 2D2D Approach == Method B" - see Point 3 in the release notes for Build 2008-08-AE (see http://www.tuflow.com/Release_Notes_2008_08.htm#5).

If you still have problems, please email some images of the problematic flow patterns that are occurring to support@tuflow.com and we'll have a look and provide some suggestions.

Cheers

Bill