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Merging Grids

Yadhunath E.M, modified 4 Years ago.

Merging Grids

Wind Posts: 70 Join Date: 7/4/13 Recent Posts
Hai,
I am new to XBeach and trying to run it for initial conditions. Now I would like to know is it possible to make Variable grid size for XBeach. Especially at near shore having a gridsize of 5m (dx and dy). I found an matlab function xb_grid_merge is it possible using this anybody tried this before??

Other wise i know that grid generated by delft3d can be used in XBeach, so if i make three different grids of varying size from offshore to shoreline using delft , Is that possible to merge using xb_grid_merge function. I tried but failed. or else is there any other ways to use three grids at a time in one mode??

xb_grid_delft3d - Convert XBeach grid to Delft3D and back ; if i want XBeach grid from delft3D grid how should i make use of this functio??


Please help me

Regards
Yadhunath
MM
Marco Miani, modified 4 Years ago.

RE: Merging Grids

Wind Posts: 40 Join Date: 4/1/14 Recent Posts
Yadhu,

yes you can.

D3D suite is an excellent tool for grid preparation. That would allow local refinement and bottom-adaptative mesh design.
The suite is open source (you need to request an license and license manager, it's all free of charge) and everything VERY well documented.
You also have video tutorials!!

http://oss.deltares.nl/web/delft3d/download
Enjoy.
Yadhunath E.M, modified 4 Years ago.

RE: Merging Grids

Wind Posts: 70 Join Date: 7/4/13 Recent Posts
Hi Marco,

Thanks i am currently running with grid form of delft3D only. but i cant make refinement as per my need. If i try to refine it, it refining horizontally and vertically all over the domain instead of refine only few grid points .. In other words i can'nt refine (minumum dx and dy should be 5m) grids of a particular area. I attached that grid here it was made in delft3d. Please have a look and give some suggesions,

Regards,
yadhunath

Attachments:

MM
Marco Miani, modified 4 Years ago.

RE: Merging Grids

Wind Posts: 40 Join Date: 4/1/14 Recent Posts
Yadhu, have you bothered reading the manual? I suspect you did not, because otherwise you would have seen something called "local refinement".Sending around your problems and expecting others to send it back to you, solved and polished, is unfair and will serve to nothing.

So my suggestion is: Dig and solve. Or at very least have the good grace of trying yourself before asking other to do it.
Yadhunath E.M, modified 4 Years ago.

RE: Merging Grids

Wind Posts: 70 Join Date: 7/4/13 Recent Posts
Thanks Marco,
I found something intresting regarding this. Let me try to slove it

Regards,
yadhunath
Arnold van Rooijen, modified 4 Years ago.

RE: Merging Grids

Swell Posts: 239 Join Date: 11/7/11 Recent Posts
Hi Yadhu,

Perhaps you already solved it, but it seems that you misunderstood the (structured) grid concept of Delft3D (and also XBeach). Both models use rectilinear or curvilinear grids, but in all cases your grid is specified as a matrix with equal M/N points along every row/column. This means that if you refine a certain area, this will always radiate out along the entire grid. So if you want higher resolution in x-direction near the shoreline, you will have this for all y-locations. And if you want a higher resolution in an area of interest around a range of y-values, this fining will be applied to all x-values. For a structured grid approach there is simply no other option in one grid.

The option would be to use either nesting or domain decomposition, but for that I would recommend you to post your question on the Delft3D forum. THere should be many people that have lots of experience with that in Delft3D.

Hope this helps.

Cheers,
Arnold

PS: in future you will be able to actual local refinements using the unstructured code (Delft3D-Flexible Mesh), but that is still in development
Bas Hoonhout, modified 4 Years ago.

RE: Merging Grids

Infra-gravity Posts: 362 Join Date: 5/20/11 Recent Posts
Hi Yadhunath,

The XBeach Matlab toolbox provides some very simple functions to generate rectilinear grids.
If you want something more advanced use the Delft3D tools instead. You can generate a single grid with varying grid size and read it directly into XBeach by setting gridform=delft3d in params.txt.

There is no need to use xb_grid_merge or any Matlab function. The xb_grid_merge will not give you a varying grid also.

Bas