Dynamical friction against velocity for the superfluid with varying , and for the zero temperature and the fully normal fluid limits. The results from finite-time linear perturbation theory are shown with dotted lines of the same colors. Even with the critical velocity included, the superfluid case gives a dynamical friction force of the same magnitude as the zero temperature limit. When is decreased, the superfluid approaches the fully normal fluid limit as thermal counterflow is increasingly limited. The sound speeds c_T = 0 and c_n are indicated by the vertical dotted lines.