Creating a one-triangular-element-wide interface
Hello everyone,
I am trying to create a mesh, and although I have used gmsh for a long time now, I might be ignorant with regards to its more advanced options, so apologies if this question has a very simple solution.
I have a two-dimensional mesh with a very thin channel that is 1 km wide, and I want that channel to be exactly 1 element wide (see figure below). By fiddling around with the mesh size I impose on the points that span the channel (I currently use 1.1 km), I can kind of get what I want, but only in a very small region (circled). I would like to have this kind of mesh in the rest of the channel too (except in the shallowest part, where I need a high resolution, because the resulting calculations on the mesh show numerical artefacts otherwise), but I don’t know how to impose it. I’ve been trying a lot of different maximum mesh sizes, but that doesn’t help. I have also been looking into the option of creating a hybrid mesh with a structured mesh inside the thin channel, but as the code we are using can only solve for one type of element at the time, this is not an option. Therefore, having a one-element wide triangular mesh in the channel (like in the circled region in the figure) seems to be the only viable option.
Does anyone have any idea how to get this to work? I also attach my .geo file, so you can have a look at what the mesh looks like, if needed.
Thanks so much, Iris