“…The
–nonconforming quadrilateral finite element
[27] has an advantage in computing stiffness matrice as the gradient of linear polynomials is constant in each quadrilateral as well as it has the smallest DOFs (degrees of freedom) for a given quadrilateral mesh. This finite element have been applied to fluid dynamics, elasticity, and electromagnetics
[8, 15, 16, 23‐26, 28]. Unlikely other finite elements, the
–nonconforming finite element space is strongly tied with boundary conditions due to the element‐by‐element “dice rule constraint” (See (3.1)).…”