Author(s): Xu Guobin; Lian Jijian
Linked Author(s): Jijian Lian
Keywords: River dynamics; Open system; Principle of minimum rate of energy dissipation; Principle of minimum entropy production; Principle of maximum entropy
Abstract: The minimum rate of energy dissipation of flow has inspired considerable interest of many researchers, since it was proposed by Helmholtz in 1868. In this paper, according to the theories of non-equilibrium thermodynamics, it is shown that the minimum entropy production is equivalent to the minimum rate of energy dissipation. Based on the principle of minimum entropy production, the mathematical calculations between the entropy production and the entropy current are performed starting from the Gibbs function in thermodynamics, and by use of the equations of continuity, motion and energy in flow mechanics. An expression of the minimum rate of energy dissipation is obtained. An alluvial river is able to adjust itself. In this paper, it is also shown that the self-adjustments of a river are subject to the principle of minimum entropy production or the minimum rate of energy dissipation rather than the principle of maximum entropy.