Correlation in thermal fluctuations induced by phase-locked hydrodynamic modes

Xiaohui Deng, Xiaoping Wang, and Ping Sheng
Phys. Rev. E 103, 053106 – Published 18 May 2021

Abstract

Thermal fluctuations constitute a fundamental equilibrium phenomenon whose spatial and temporal correlations are governed by the relevant scales of molecular collisions. From the continuum point of view, thermal fluctuations in a fluid can be regarded as comprising a multitude of hydrodynamic modes (HMs) with random phases, each one having one degree of freedom. We show that in a two-dimensional fluid channel with the Navier slip boundary condition, in which the HMs are represented by periodic arrays of vortex and antivortex pairs, periodic modulation of the slip boundary condition can selectively suppress noncommensurate HMs while phase lock the remaining eigenmodes. As a result, thermal fluctuations would exhibit mesoscopic-scale spatial correlations, manifest as a spatially varying diffusion constant when evaluated from the fluctuation-dissipation theorem. Good agreement is shown with the molecular dynamics results. Such manifestation of equilibrium collective motion implies that instead of just being an alternative mathematical basis for expressing thermal fluctuations, in mesoscopic systems the HMs may be manipulated to have physical consequences very different from those expected in bulk fluid.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
1 More
  • Received 29 November 2020
  • Revised 29 April 2021
  • Accepted 3 May 2021

DOI:https://doi.org/10.1103/PhysRevE.103.053106

©2021 American Physical Society

Physics Subject Headings (PhySH)

Fluid DynamicsStatistical Physics & Thermodynamics

Authors & Affiliations

Xiaohui Deng1, Xiaoping Wang2, and Ping Sheng1,*

  • 1Department of Physics, HKUST, Clear Water Bay, Kowloon, Hong Kong, China
  • 2Department of Mathematics, HKUST, Clear Water Bay, Kowloon, Hong Kong, China

  • *sheng@ust.hk

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 103, Iss. 5 — May 2021

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review E

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×