Nitsche’s method [12] was introduced for imposing essential boundary conditions weakly in the finite elements
method approximation of Poisson equation with Dirichlet data. Basically, Nitsche’s approach consists in penalizing
the difference between the approximate solution and the Dirichlet boundary data rather than trying to interpolate that
data directly. It leads to symmetric positive definite linear systems that can be solved very quickly for instance using
gradient or multigrid numerical methods.The main advantage of Nitsche’s method is that it keeps the convergence rate
of the finite elements method [13], as opposed to the standard penalty method.