Fluid-particle interactions and fluctuation-dissipation relations I -- General linear theory and basic fluctuational patterns

Fuente: arXiv
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Hauptverfasser: Giona, Massimiliano, Procopio, Giuseppe, Pezzotti, Chiara
Format: Preprint
Veröffentlicht: 2024
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author Giona, Massimiliano
Procopio, Giuseppe
Pezzotti, Chiara
author_facet Giona, Massimiliano
Procopio, Giuseppe
Pezzotti, Chiara
contents The article provides a unitary and complete solution to the fluctuation-dissipation relations for particle hydromechanics in a generic fluid, accounting for the hydrodynamic fluid-particle interactions (including arbitrary memory kernels in the description of dissipative and fluid inertial effects) in linear hydrodynamic regimes, via the concepts of fluctuational patterns. This is achieved by expressing the memory kernels as a linear superposition of exponentially decaying modes. Given the structure of the interaction with the internal degrees of freedom, and assuming the representation of the thermal force as a superposition of modal contributions, the fluctuation-dissipation relation follows simply from the moment analysis of the corresponding Fokker-Planck equation, imposing the condition that at equilibrium all the internal degrees of freedom are uncorrelated with particle velocity. Moreover, the functional structure of the resulting equation of motion corresponds to the principle of complete decoupling amongst the internal degrees of freedom. The theory is extended to the case of confined geometries, by generalizing previous results including the effect of fluid inertia.
format Preprint
id arxiv_https___arxiv_org_abs_2412_19166
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fluid-particle interactions and fluctuation-dissipation relations I -- General linear theory and basic fluctuational patterns
Giona, Massimiliano
Procopio, Giuseppe
Pezzotti, Chiara
Statistical Mechanics
The article provides a unitary and complete solution to the fluctuation-dissipation relations for particle hydromechanics in a generic fluid, accounting for the hydrodynamic fluid-particle interactions (including arbitrary memory kernels in the description of dissipative and fluid inertial effects) in linear hydrodynamic regimes, via the concepts of fluctuational patterns. This is achieved by expressing the memory kernels as a linear superposition of exponentially decaying modes. Given the structure of the interaction with the internal degrees of freedom, and assuming the representation of the thermal force as a superposition of modal contributions, the fluctuation-dissipation relation follows simply from the moment analysis of the corresponding Fokker-Planck equation, imposing the condition that at equilibrium all the internal degrees of freedom are uncorrelated with particle velocity. Moreover, the functional structure of the resulting equation of motion corresponds to the principle of complete decoupling amongst the internal degrees of freedom. The theory is extended to the case of confined geometries, by generalizing previous results including the effect of fluid inertia.
title Fluid-particle interactions and fluctuation-dissipation relations I -- General linear theory and basic fluctuational patterns
topic Statistical Mechanics
url https://arxiv.org/abs/2412.19166