La Houille Blanche
Number 5, Août 1970
|Page(s)||427 - 432|
|Published online||23 March 2010|
Les principes en mécanique des milieux continus
Professeur à la Faculté des Sciences de Grenoble.
The author only considers bodies governed by the principle of local properties. He gives an explicit formulation for the (universal) spatial isotropy principle and the (possible) isotropy of the law governing a body. After a statement of evident consequences of this a number of examples are given, showing that whether spatial isotropy results in an isotropic relationship depends on the type of law involved. The author then states the objectivity principle, which can be interpreted either in its strict sense, i.e. disregarding spatial isotropy, or in its wider sense embracing the latter. He makes a distinction between the effect of definition and expression datums, also between quantities that are naturally objective because they do not depend on the definition datum and quantities made objective by statement of their definition datum. He then draws attention to the difference between datums defined before definition of the flow of the body and datums connected with the actual flow, e.g. rheological datums. Finally, he explains why it is preferable physically to express the relationship in terms of a rheological datum, but that in approaching concrete problems mathematically it is still essential to express the original relationship in rheological datum terms.
© Société Hydrotechnique de France, 1970