open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear Users,

I am a newbie Blue Kenue User and i would like to refine my mesh according to the slope.
I followed the instructions listed above as in

1. generate a mesh - interpolate bathymetry - extract slope
2. use mesh(slope) as density function (density mesh is slightly bigger than 'final mesh')

but instead of refining, the mesh size gets bigger, especially in the middle of the domain. Do I miss a step when trying to refine the mesh ?

you'll find the meshes attached:


mesh_032(slope) - mesh with slope information
mesh_fin_1 - mesh i want to refine using the slope
mesh_fin_1-density - mesh generated using density function






Thanks !!

Hello,
You need to 'manipulate' the extracted slopes so that the resulting mesh value reflects the desired mesh size. Assuming you want to make the element size smaller the greater the slope you should employ a function (in BK's calculator) like:So if the slope is, say 5 degrees, you will end up with a mesh element size of 1m. If the slope gets 10 degrees, the mesh element will reduce to 0.5m.
Regards,
Costas

Thank you very much - it worked :)

I have another question relating to the refinement of a mesh via a density mesh.

To create this density mesh, is it possible to have 2 conditions when doing a calculator operation ?

For example
- if bathymetry is deeper then X
-> do nothing
- else
-> apply an expression.

Thank you in advance !

There is no such (conditional) functionality in the calculator. However, I believe that it is possible to do what you want using other means. If you can provide a pseudocode of what you would like to accomplish, maybe I can think of something.

The aim is to create a mesh of the North East Atlantic Ocean. Therefor I created a mesh which i refined using the slope I extracted, which worked pretty well all over the domain (in fact i would like to refine the zone around the passage from ocean floor to continental shelf).

The refined model has also a finer mesh size when the bathymetry is very deep, but i don't need the refinement in this area.

Basically the condition would be

if slope higher then X and bathymetry less than Y
-> refine the mesh
else (if small slope and great depth)
-> keep the mesh as it is.

I hope it is a bit clearer than in my precedent post.

Perhaps using multiple density objects would get you where you need to be...

Kindly,
Alan

Also, the Blue Kenue manual (p. 120) lists all functions... perhaps you can make use of ">" or "<" function

Kindly,
Alan

As Alan said, you can use multiple density objects and the resulting mesh would be the smallest of the two. You can create two density objects, one based on the slope and one based on the depth. If you make sure the depth-based density object is everywhere larger than the slope-based object, except for the continental shelf transition, then you're done.

1. First create the depth-based density object that produces the desired element size irrespective of slope.
2. Then create the slope-based density object that is finer than the first only where the slope is great.

Work with the above and we then we can provide more advice on your formulation.