Exact spherically-symmetric inhomogeneous model with n perfect fluids
  We present the exact equations governing the dynamics of a
spherically-symmetric inhomogeneous model with n decoupled and non-comoving
perfect fluids. Thanks to the use of physically meaningful quantities we write
the set of 3+2n equations in a concise and transparent way. The n perfect
fluids can have general equations of state, thus making the model extremely
flexible to study a large variety of cosmological and astrophysical problems.
As applications we consider a model sourced by two non-comoving dust components
and a cosmological constant, and a model featuring dust and a dark energy
component with negligible speed of sound.
