In this paper a general hydrodynamic mode coupling theory of equilibrium fluctuations in simple liquids is developed from molecular considerations. The approach developed hem avoids the shortcomings of previous mode coupling theories by adopting a complete hierarchy of equations for the slow modes of a hydrodynamic system and solving it formally through the N ordering approximation scheme devel...

Many features of granular media can be modelled as a fluid of hard spheres with inelastic collisions. Under rapid flow conditions, the macroscopic behavior of grains can be described through hydrodynamic equations. At lowdensity, a fundamental basis for the derivation of the hydrodynamic equations and explicit expressions for the transport coefficients appearing in them is provided by the Boltz...

Using Newtonian molecular dynamics we study a gas of inelastic hard disks subject to shear between two planar parallel thermal walls. The system behaves like a Couette flow and it is tuned to produce a steady state that ideally has uniform temperature, uniform density, no energy flux and a linear velocity profile for restitution coefficient in the wide range: 0:3prp1. It is shown that Navier–St...

Lattice Boltzmann equations using multiple relaxation times are intended to be more stable than those using a single relaxation time. The additional relaxation times may be adjusted to suppress non-hydrodynamic modes that do not appear directly in the continuum equations, but may contribute to instabilities on the grid scale. If these relaxation times are fixed in lattice units, as in previous ...

The knowledge of the propagation of flood waves, in natural channels, through Saint Venant's equations, has been object of studies on the part of engineers and scientists, along years. With the progress of the digital computers, the mathematical models become a great option, in the analysis of this class problem. In this context, the uses of numerical models, in the treatment of the hydrodynami...

Abstract—In this work, numerical simulations were carried out using a specific CFD code in order to study the performance of an innovative Scraped Surface Heat Exchanger (SSHE) with helical ribbons for Bingham fluids (threshold fluids). The resolution of threedimensional form of the conservation equations (continuity, momentum and energy equations) was carried out basing on the finite volume me...

A simple method to determine mode-coupling memory functions in generalized Langevin equations is obtained by explicitly expressing the random force of the slow hydrodynamic modes in terms of pair interactions in liquids and by Gaussian factoring the resulting multiple-point time correlation functions into products of linear correlation functions. The approach is used to derive the mode-coupling...

A good representation of mesoscopic fluids is required to combine with molecular simulations at larger length and time scales [De Fabritiis, Phys. Rev. Lett. 97, 134501 (2006)]. However, accurate computational models of the hydrodynamics of nanoscale molecular assemblies are lacking, at least in part because of the stochastic character of the underlying fluctuating hydrodynamic equations. Here ...

We consider a coarse-grained description of a collection of self-propelled particles given by hydrodynamic equations for the density and polarization fields. We find that the ordered moving or flocking state of the system is unstable to spatial fluctuations beyond a threshold set by the self-propulsion velocity of the individual units. In this region, the system organizes itself into an inhomog...

The relativistic kinetic equations for the two domains separated by the hypersurface with both spaceand time-like parts are derived. The particle exchange between the domains separated by the time-like boundaries generates source terms and modifies the collision term of the kinetic equation. The correct hydrodynamic equations for the “hydro+cascade” models are obtained and their differences fro...