The no-slip condition at the western boundary of a homogeneous ocean minimizes energy

It is not obvious, a priori, that the no-slip boundary condition is suitable for ocean circulation models based on quasi-geostrophic equations. But the no-slip condition is the one that minimizes the kinetic energy of the western boundary layer of a wind-driven ocean governed by fourth-order quasi-geostrophic equations. Moreover, the case of a very thin boundary layer is correctly described by the asymptotic solution when the no-slip condition is chosen. Then, it is physically sound to use the no-slip condition even in the western boundary of analytical or numerical ocean circulation models, be they linear or nonlinear.