Hi. I studied the blog for applying the neuman boundary contion in one dimension. The blog link is https://cn.comsol.com/blogs/implementing-the-weak-form-in-comsol-multiphysics/
but i am facing problem in applying the weak boundary conditions in 2d, for example how to apply for elliptical shape, when we solving the Naveir stokes equation for u, v and p. Please can some one help me. Thanks.