DEVELOPMENT OF THE PRINCIPLE FOR THE ACTUAL STATE OF A PHYSICAL SYSTEM

The energy principle for the actual state of a physical system with distributed parameters is formulated using the example of problems formulations in linear theories, fluid, and thermal conductivity. It is shown that if the system state variables are chosen in appropriate way, all the considered problems of mathematical physics are reduced to one universal formulation. This description of the system makes it possible not only to evaluate the quality of approximate solutions, but also to estimate the perfection of the mathematical model used.