  The collective behavior of animals can be modeled by a system of equations of
continuum mechanics endowed with extra terms describing repulsive and
attractive forces between the individuals. This system can be viewed as a
generalization of the compressible Euler equations with all of its unpleasant
consequences, e.g., the non-uniqueness of solutions. In this paper, we analyze
the equations describing a viscous approximation of a generalized compressible
Euler system and we show that its dissipative measure-valued solutions tend to
a strong solution of the Euler system as viscosity tends to 0, provided that
the strong solution exists.
