Non rectangular domains

[pcosme]

It would be extremely interesting to allow the simulation on non-rectangular domains, particularly with a trapezoidal shape, varying the width of the channel.

Rather than change the grid itself I think it would be easier to implement it on the Boundary conditions, we should think about it

[pcosme]

Bear in mind that with such geometry the closed and no-slip boundary conditions are not written directly in v_x and v_y but rather on the tangent and normal velocity to the interface

[pcosme]

Regarding the non-rectangular domains, it may also be important to consider obstacles and/or constrictions along the flow, like those investigated by Andrew Lucas in this article : https://arxiv.org/pdf/2105.01075v2.pdf