Mesh refinement for downward facing step with gmsh
 

Hello everyone,

I am a new user of gmsh3. I would like to mesh a downward facing step with structured cells. The black and white mesh (mesh.png) is similar to the one a manage to do. However, the downstream of the step edge should be meshed with fine cells and the fine area mesh is expanded in the downstream following a triangle shape as seen on the attached picture with colors (grid-plot.jpg).

I managed to perform progressing mesh in the x (streamwise direction) and y (wall normal direction) directions with constant mesh progression. However, I do not succeed in having a mesh progression in the y direction that depend on the x direction (which permit obtaining the triangular shape of fine mesh region). How can I do that with gmsh3 ?

Thanks a lot,
Boone