2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/151596A nonlinear two-fluid stochastic hydrodynamical description of velocity and concentration fluctuations in sedimenting suspensions is constructed, and analyzed using self-consistent (SC) and renormalization group (RG) methods. The advection of particles by velocity fluctuations is shown to be ``relevant'' in all dimensions $d < 6$ . Both RG and SC analyses predict a strong reduction in the dependence of velocity fluctuations on system-size $L$ relative to the $L^{1/2}$ obtained in the linearized theory of Caflisch and Luke [Phys. Fluids {\bf 28}, 785 (1985)]. This is an important step towards resolving a ten-year old puzzle in the field.Four pages, revtex, two .eps files, uses epsf.stySoft Condensed Mattertext