Re: [Anuga-user] Actual height of wall using breaklines

[Gareth D. <gar...@gm...>]

Hi Ananth,

 From your code snippet, it looks like your "breaklines" are actually 
"polygons" with a given specified height. I suspect this has been 
modified from the runMerewether.py example? In the latter script, 
'breaklines' are used to force edge boundaries in the mesh (defining 
buildings in that case). Then we set the elevation inside the buildings 
to a 'house-height'. It looks like your code is similar.

I'm not 100% sure -- but I suspect this is not really what you want to 
do. If it really is what you want, then be careful that you are not 
'accidently smoothing' the elevation (i.e. be sure to set the elevation 
quantity at centroids, not vertices). Also, be careful that your "wall 
polygons" are wide enough to include a continuous set of triangles.

An alternative approach is to keep using "breaklines" to ensure that  
mesh-edges follow some specified line (i.e. your walls). Next, instead 
of defining the wall using a group of cells, you can use a "riverwall" 
operator to tell ANUGA what the "edge-elevation" should be. In this 
case, the "riverwall" is like a 'thin discontinuity in elevation' 
between 2 triangles. Flow over this "weir" can be computed using some 
mixture of a weir equation, and the Riemann flux function (for details 
see the documentation of riverWalls in the code).

An example which uses the riverwall functionality like what I describe 
is here: 
https://github.com/GeoscienceAustralia/anuga_core/tree/master/validation_tests/behaviour_only/weir_1

Probably that's the easiest place to look to get started. However, there 
are a bunch of other examples which use the riverwall functionality  in 
the same subdirectory. It is also used in a generic script here: 
https://github.com/GeoscienceAustralia/anuga_core/tree/master/examples/cairns_excel. 


Cheers,
Gareth.


On 29/1/19 7:34 pm, Ananth Wuppukondur wrote:
> Hi,
>
> I'm using the following to define elevation of a wall using 'breaklines'.
>
> for i in range(len(breaklines)):
>     breaklines[i] = breaklines[i] + [breaklines[i][0]]
>     house_addition_poly_fun_pairs.append(
>     [ breaklines[i], house_height])
> house_addition_poly_fun_pairs.append(['All', 0.])
>
> The simulation runs without any error. However, the results are not as 
> expected when comparing to experiments. I suspect this difference in 
> experiments and simulations could be because of some issue in 
> translating wall elevation from the above function. I've two cases: 1. 
> With wall defined by breaklines, 2. without any wall. The second case 
> matches well with corresponding experimental results. But not the 
> first case. Is there any command to display the elevation assigned to 
> the breaklines? Or would you recommend any alternative for defining a 
> wall? Thanks in advance.
>
> -- 
> -- 
> Best wishes,
> *Ananth Wuppukondur,*
> PhD candidate | Coastal Research Group
> School of Civil Engineering | The University of Queensland
> Brisbane, Australia.
> /Web-links:/Personal webpage 
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>
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