Laws of Energy Gradient for Instabilities

Transition to turbulence is due to the instability of a laminar flow subject to a disturbance. This complicated problem can be explained using a new proposed energy gradient theory in our previous study. This theory is extended to the instability of fluid material systems in this study. The instability of fluid material systems may lead to the evolution of natural environments and the occurrence of catastrophic events in the world. To better describe these phenomena and to understand the physical mechanism behind them are very important. In order to more generally describe the instability of fluid material systems, laws of energy gradient are summarized for static and motion systems, respectively. These laws could be applicable to various flow problems and material systems. Examples are shown that many events in the world could be explained using these laws.