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Particle Tracking

Francesco Enrile, modified 2 Months ago.

Particle Tracking

Youngling Posts: 21 Join Date: 3/25/12 Recent Posts

Is it possible to use the module particle tracking with a spherical grid?

delft3d-part
AM
Arjen Markus, modified 2 Months ago.

RE: Particle Tracking

Jedi Knight Posts: 173 Join Date: 1/26/11 Recent Posts

In principle yes, that is possible. The one thing I do not know by heart is whether the grid distances and surface areas are converted correctly to meters and square meters instead of degrees and square degrees. Unfortunately I have no time today to dive into that, but the crucial point would be to see what the grid coordinates are if you view the grid via the LGA/CCO files, as that is where Delft3D-PART gets its geometrical information from.

You can visualise the grid in these files via QuickPlot. Check the range, that ought to indicate whether the grid contains the coordinates in meters or degrees.

Another thing though: the use of spherical coordinates suggests that your model covers a substantial area. You may need to use a large number of particles (in the order of millions) to cover that area with sufficient accuracy.

Francesco Enrile, modified 2 Months ago.

RE: Particle Tracking

Youngling Posts: 21 Join Date: 3/25/12 Recent Posts

If I open lga/cco files the x and y coordinates show lon/lat values. I compiled Delft3D tag 7545 on linux with gfortran. When I launch Deft3D-PART I get the following message:

 

 

  WARNING: Your x-coordinates are in the range [-180,180] and your
           y-coordinates are in the range [-90,90]. You might have
           a spherical grid. This is not yet supported by PART.

 

I imagine that I must convert my spherical grid in a cartesian one.

AM
Arjen Markus, modified 2 Months ago.

RE: Particle Tracking

Jedi Knight Posts: 173 Join Date: 1/26/11 Recent Posts

I was unaware that Delft3D-PART actually checks for that :). Yes, like I said the problem is that it derives its geometry directly from the LGA/CCO file and as long as that is given in meters, all should work. Converting the model to a cartesian one will get around this.