Generalized dynamical density functional theory for classical fluids and the significance of inertia and hydrodynamic interactions

TL;DR

This paper develops a generalized dynamical density functional theory for classical fluids that incorporates inertia and hydrodynamic interactions, showing strong agreement with detailed Langevin simulations and unifying various existing models.

Contribution

It introduces a comprehensive DDFT framework that includes inertia and hydrodynamics, bridging gaps between different theoretical approaches.

Findings

DDFT matches Langevin dynamics results accurately.

Recovers existing DDFTs and Navier-Stokes-like equations in specific limits.

Highlights importance of inertia and hydrodynamics in non-equilibrium fluid behavior.

Abstract

We study the dynamics of a colloidal fluid including inertia and hydrodynamic interactions, two effects which strongly influence the non-equilibrium properties of the system. We derive a general dynamical density functional theory (DDFT) which shows very good agreement with full Langevin dynamics. In suitable limits, we recover existing DDFTs and a Navier-Stokes-like equation with additional non-local terms.