Équation de continuité

Résumé

vignette|mécanique des fluides En mécanique des fluides, le principe de conservation de la masse peut être décrit par l'équation de continuité sous plusieurs formes différentes : locale conservative (dérivée en temps normale), locale non conservative (la dérivée en temps suit la particule dans son mouvement), ou intégrale. Suivant les problèmes posés, c'est l'une ou l'autre de ces équations qui pourra être retenue, toutes étant équivalentes. On note ici : *\rho = \rho(\vec{x},t) : la masse volumique du fluide au point repéré par le vecteur \vec x à l'instant t

\vec{U} = \vec{U}(\vec{x},t) : la vitesse d'une particule de fluide se trouvant au point repéré par le vecteur \vec x à l'instant t

Forme locale Cette écriture est la plus générale et la plus répandue: \frac{\partial \rho}{\partial t} + \vec{\nabla} \cdot \left( \rho \ \vec{U} \right) = 0.En faisant interve

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