Energy and energy flux densities given by Eqs. (19) and (20) for (a) horizontal and (b) vertical polarizations. Here the subscript “h” (“v”) represents the horizontal (vertical) case. The energy densities for both polarizations are depicted with black lines. Energy flux densities are computed in two ways: by considering all boundaries and by excluding the left symmetric boundary and bottom reflective boundary. These two cases are shown as red and blue curves, respectively.