Bonet i Avalos, JosepRubí Capaceti, José MiguelRodríguez, R.Pérez Madrid, Agustín2009-09-282009-09-2819901050-2947https://hdl.handle.net/2445/9464We analyze the light-scattering spectrum of a suspension in a viscoelastic fluid under density and velocity gradients. When a density gradient is present, the dynamic structure factor exhibits universality in the sense that its expression depends only on the reduced frequency and the reduced density gradient. For a velocity gradient, however, the universality breaks down. In this last case we have found a transition point from one to three characteristic frequencies in the spectrum, which is governed by the value of the external gradient. The presence of the viscoelastic time scales introduces a shift in the ``critical¿¿ point.9 p.application/pdfeng(c) The American Physical Society, 1990Mecànica estadísticaFluctuacions (Física)Statistical mechanicsFluctuations (Physics)info:eu-repo/semantics/article38582info:eu-repo/semantics/openAccess