Dissipation of kinetic energy in two-dimensional bounded flows

The role of no-slip boundaries as an enstrophy source in two-dimensional (2D) flows has been investigated for high Reynolds numbers. Numerical simulations of normal and oblique dipole-wall collisions are performed to investigate the dissipation of the kinetic energy E(t), and the evolution of the enstrophy [Omega] (t) and the palinstrophy P(t). It is shown for large Reynolds numbers that dE(t)/dt = ?2 [Omega] (t)/Re [[proportional]] 1/ [sqrt(Re)] instead of the familiar relation dE(t)/dt [[proportional]] 1/Re as found for 2D unbounded flow