Fig. 4.

Normalized potential energy of a vapor bubble resting on the wall of a cylinder as a function of its normalized volume . The Young’s contact angle is θ = 120^o. The different plots correspond to different values of the liquid pressure P_L. The shape of the bubble surface is represented for different volumes. At a critical volume V_c, the bubble becomes unstable and spreads over the pore section, forming two disconnected menisci. The maximum value ΔΩ_c is equal, or very close, to ΔΩ just before instability. (Inset) The reduced critical volume as a function of the reduced liquid pressure P_LR_p/2γ_lυ.