On the propagation of energy in linear conservative waves |
| |
Authors: | L. J. F. Broer |
| |
Affiliation: | (1) Mededeling No. 67 uit het Laboratorium voor Aero- en Hydrodynamica der Technische Hogeschool te Delft, The Netherlands |
| |
Abstract: | Summary This paper is concerned with the question when and why the rate of energy propagation in a system of waves equals the group velocity. It is shown by the method of stationary phase that this equality holds, for travelling waves without dissipation, whenever this method applies. The reason why this result can be obtained by this kinematical method is investigated by a discussion of simple harmonic waves. It is shown that the choice of an expression for the energy density to be used in connection with a given wave equation is restricted by the conservation of energy in such a way that the average rate of work done divided by the average energy density always equals the group velocity. Finally some examples of wave motion are discussed to illustrate the derived formulae. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |