Numerical study of instability of fluid black holes

Recently neutral and charged black-hole solutions were found for static perfect fluid with the equation of state $$p(r)=-\rho (r)/3$$ , only as well in presence electric field. In those works, stability black holes studied an analytic manner, which concluded that are unconditionally unstable. this work, we focus particularly on numerical study instability. For without horizons, solve perturbation equations numerically find unstable mode functions.