Groupe de Travail des Thésard·es du LJLL

The Boltzmann collision integral plays a fundamental role in kinetic theory, governing the statistical behavior of particle interactions in rarefied gases. In this talk, we begin with a review of its definition, local conservation laws, and the (local) H-theorem. We then introduce delocalized generalizations of the collision integral, including the Enskog, Povzner, and Cercignani’s soft-sphere models, which account for nonlocal effects in dense gases. Finally, we discuss their implications for macroscopic descriptions, presenting a conservative formulation for delocalized collision integrals and establishing a local H-theorem in this framework. These results provide insight into the transition from kinetic to hydrodynamic descriptions in dense gas dynamics.

Mar 19, 2025 5:00 PM — 6:00 PM