In our cubic lattice model this is defined to be pressure at which fluid in at least one pore on the side of the model material opposite to the side that contains sinks evaporates. This means that connected cluster has grown from the side of model material that contains sinks to the opposite side. The size of this cluster of pores is comparable to the size of the whole model system, since the cluster spans it. In cubic lattices with the same pore size distribution connected cluster tends to form in a very narrow pressure range. Pressure of connected cluster formation.
Vapor forms a connected cluster inside the system and spans it.
Pores containing fluid form a number of disconnected clusters filling the space that has not been invaded yet by the vapor cluster. Connected cluster of pores containing vapor Fig 3. Pores containing fluid Fig 4. Thus most of the avalanches take place after the connected cluster is formed. This demonstrates that system has large avalanches near its critical pressure and behaves similarly right before and right after connected cluster formation.