As shown in Figure 3, the critical mass flux or flow velocity for fluidelastic instability in Freon can generally be clearly defined by the ... The results are presented in the form of an instability diagram in Figure 10. ... 1.0 10.0 100.0 Damping (2n^nVpD2) + Freoo-134a, Present Work ac Freon-22, Pettigrew et al. ... The change in behaviour is particularly dramatic for the tube bundle in Freon-22 two-phase flow.