Percolation and invasion percolation in the presence of mobile impurities
Reginaldo A Zara; Roberto N Onody; Reginaldo A Zara; Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil; Roberto N Onody; Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
Журнал:
Journal of Physics: Condensed Matter
Дата:
2000-07-17
Аннотация:
We present a model for the solidification process of two immiscible fluids interacting repulsively with mobile impurities on a two-dimensional square lattice. In the space of the fluids and impurity concentrations, the phase diagram exhibits a critical curve separating a percolating from a non-percolating phase. Estimated values for the fractal dimension and the exponent β of the order parameter reveal that the critical exponents do not vary along this curve, i.e., they are independent of the impurity concentration. The universality class is that of the ordinary percolation. On the basis of the ideas of the dynamic epidemic and invasion percolation models, we also propose a model that may be relevant to cleaning porous media by fluid injection. An analysis of the acceptance profile, the fractal dimension and the gap exponent strongly indicate that this model belongs to the universality class of the ordinary invasion percolation.
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