  Impulsive dynamical systems, modeled by a continuous semiflow and an impulse
function, may be discontinuous and may have non-intuitive topological
properties, as the non-invariance of the non-wandering set or the non-existence
of invariant probability measures. In this paper we study dynamical features of
impulsive flows parameterized by the space of impulses. We prove that impulsive
semiflows determined by a C1-Baire generic impulse are such that the set of
hyperbolic periodic orbits is dense in the set of non-wandering points which
meet the impulsive region. As a consequence, we provide sufficient conditions
for the non-wandering set of a typical impulsive semiflow (except the
discontinuity set) to be invariant. Several applications are given concerning
impulsive semiflows obtained from billiard, Anosov and geometric Lorenz flows.
