Long time tails and hydrodynamics in dissipative particle dynamics

✍ Scribed by M. Serrano; P. Español; I. Zúñiga

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 48 KB
• Volume: 121-122
• Category: Article
• ISSN: 0010-4655
• DOI: 10.1016/s0010-4655(06)70137-0

✦ Synopsis

Dissipative Particle Dynamics allows the sinmlation of fluids in the Brownian regime where thermal fluctuations are important. The fluid is modeled in terms of mesoscopic particles that move following the flow field according to the action of dissipative and random forces . It is an ideally suited off-lattice teclmique very flexible for modelling complex fluids [2] which requires simple molecular dynamic codes.

In this work we study the detailed dynamics of the dissipative particles by looking at its velocity autocorrelation function. We observe that in the regimes of interest for simulations, the velocity autocorrelation function presents pronounced algebraic long time tails which are a reflection of the hydrodynamic behaviotu" of these particles, as desired. However, the presence of these tails renders the evaluation of the transport coefficients obtained with kinetic theory under the molecular chaos hypothesis less useful . Actually, these tails explain the observed discrepancies between the viscosity measured in the simulations and the predictions of kinetic theory .