Hydrodynamic fluctuations in thermostatted multiparticle collision dynamics

Hijar, H.; Sutmann, G.

doi:10.1103/PhysRevE.83.046708

Journal Article

PreJuSER-6877

Hydrodynamic fluctuations in thermostatted multiparticle collision dynamics

Hijar, H.FZJ* ; Sutmann, G.FZJ*

2011
APS College Park, Md.

Physical review / E 83(4), 046708 (2011) [10.1103/PhysRevE.83.046708]

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Please use a persistent id in citations: http://hdl.handle.net/2128/9320 doi:10.1103/PhysRevE.83.046708

Abstract: In this work we study the behavior of mesoscopic fluctuations of a fluid simulated by Multiparticle Collision Dynamics when this is applied together with a local thermostatting procedure that constrains the strength of temperature fluctuations. We consider procedures in which the thermostat interacts with the fluid at every simulation step as well as cases in which the thermostat is applied only at regular time intervals. Due to the application of the thermostat temperature fluctuations are forced to relax to equilibrium faster than they do in the nonthermostatted, constant-energy case. Depending on the interval of application of the thermostat, it is demonstrated that the thermodynamic state changes gradually from isothermal to adiabatic conditions. In order to exhibit this effect we compute from simulations diverse correlation functions of the hydrodynamic fluctuating fields. These correlation functions are compared with those predicted by a linearized hydrodynamic theory of a simple fluid in which a thermostat is applied locally. We find a good agreement between the model and the numerical results, which confirms that hydrodynamic fluctuations in Multiparticle Collision Dynamics in the presence of the thermostat have the properties expected for spontaneous fluctuations in fluids in contact with a heat reservoir.

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Note: H. H. acknowledges financial support from DAAD, Germany (2008), and DGAPA-UNAM, Mexico (2009-2010). G. S. would like to thank G. Gompper and R. Winkler for helpful discussions.

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