Abstract
The irreversible evolution of a model for ballistic coalescence of spherical particles, whereby colliding particles merge into a single, larger sphere with conservation of mass and momentum, is analyzed on the basis of scaling assumptions, mean-field theory, and kinetic theory for arbitrary dimensionality and size-mass relation. The asymptotic growth regime is characterized by scaling laws associated with the instantaneous mean mass and kinetic energy of the particles. A hyperscaling relation between the mass and energy exponents is derived. The predictions of the theoretical analysis are tested by extensive simulations of the two-dimensional version of the model. Due to multiple coalescence events, the exponents are found to be nonuniversal (i.e., density dependent) and to differ significantly from the mean-field predictions. The distribution of masses turns out to be universal and exponential. Particle energies follow a Boltzmann distribution, with a time-dependent temperature, or relax toward such a distribution, even when the initial distribution is highly non-Maxwellian. In the case where the particles are “swollen” [i.e., the size-mass relation involves the Flory exponentv=3/(d+2)], an asymptotic scaling regime is observed only for sufficiently low initial packing fractions. At higher densities, the irreversible evolution terminates in a “catastrophic” coalescence event involving all remaining particles.
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References
T. A. Witten and L. M. Sanders,Phys. Rev. Lett. 47:1400 (1981).
P. Meakin, InPhase Transitions and Critical Phenomena, Vol. 12, C. Domb and J. L. Lebowitz, eds. (Academic Press, London, 1988).
P. Meakin,Rep. Prog. Phys. 55:157 (1992).
G. F. Carnevale, Y. Pomeau, and W. R. Young,Phys. Rev. Lett. 64:2913 (1990).
Y. Jiang and F. Leyvraz,J. Phys. A 26:L179 (1993).
J. Piasecki,Physica A 190:95 (1992).
Ph. A. Martin and J. Piasecki,J. Stat. Phys. 76:447 (1994).
E. Trizac and J. P. Hansen,Phys. Rev. Lett. 74:4114 (1995).
P. J. Flory,Principles of Polymer Chemistry (Cornell University Press, Ithaca, New York, 1953).
S. Chapman and T. J. Cowling,The Mathematical Theory of Non-Uniform Gases, 3rd ed. (Cambridge University Press, Cambridge, 1970); P. Résibois and M. De Leener,Classical Kinetic Theory of Fluids (Wiley, New York, 1977).
B. J. Alder and T. E. Wainwright,J. Chem. Phys. 31:459 (1959).
N. M. Barber, InPhase Transitions and Critical Phenomena Vol. 8, C. Domb and J. L. Lebowitz, eds. (Academic Press, London, 1983).
Y. Pomeau and P. Résibois,Phys. Rep. 19:63 (1975).
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Trizac, E., Hansen, JP. Dynamics and growth of particles undergoing ballistic coalescence. J Stat Phys 82, 1345–1370 (1996). https://doi.org/10.1007/BF02183386
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DOI: https://doi.org/10.1007/BF02183386