Abstract
In our previous work we have performed an exact calculation using the colorless partition function of the QGP by probing the behavior of some useful thermodynamic response functions on the whole range of temperature. If the system formed in an ultra relativistic heavy ion collision reaches a state of local thermodynamic equilibrium and if it can be locally maintained during the subsequent expansion, the further evolution of the QGP and Hadronic Gas can be described conveniently by Relativistic Hydrodynamics. It requires knowledge of the equation of state, which gives a relation between pressure P, energy density epsilon, entropy densitys and sound velocityc(s). Precisely, in the present work we have performed the study of these hydrodynamical response functions, outshining the physics of the evolution of the system undergoing a deconfinement phase transition, when the colorless condition is taken into account.