2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/203048We study the effect of the inclusion of bulk brane viscosity on brane world (BW) cosmology in the framework of the Eckart's theory, we focus in the Randall-Sundrum model with negative tension on the brane.4 pages. Submitted to PLBGeneral Relativity and Quantum CosmologyRandall-Sundrum model with $λ<0$ and bulk brane viscositytext