2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/87471New types of symmetry for the Rayleigh equation are found. For small Atwood number, an analytic solution is obtained for a smoothly varying density profile. It is shown that a transition layer with a finite width can undergo some kind of stratification.7 Pages, LatexPlasma Physicstext