Physicists at IIT Kanpur unravel insights to Second Law of Thermodynamics. Prof. Mahendra Verma and research scholar Soumyadeep Chatterjee from the Department of Physics, IIT Kanpur, have discovered that 2D Euler flow—flow with zero viscosity--evolves from disorder to order. The study, “Hydrodynamic Entropy and Emergence of Order in Two-dimensional Euler Turbulence” published in Physical Review Fluids journal finds that 2D Euler flow evolves from disorder to order and that the system is out of equilibrium with an interesting energy exchange among the flow structures so as to violate the detailed energy balance. In fact, there is an inverse cascade of energy, which is responsible for the nonequilibrium behaviour of 2D Euler turbulence.