Viscous coupling of shear-free turbulence across nearly flat fluid interfaces

  title={Viscous coupling of shear-free turbulence across nearly flat fluid interfaces},
  author={Julian Charles Roland Hunt and Derek Stretch and Stephen E. Belcher},
  journal={Journal of Fluid Mechanics},
  pages={96 - 120}
The interactions between shear-free turbulence in two regions (denoted as + and − on either side of a nearly flat horizontal interface are shown here to be controlled by several mechanisms, which depend on the magnitudes of the ratios of the densities, ρ+/ρ−, and kinematic viscosities of the fluids, μ+/μ−, and the root mean square (r.m.s.) velocities of the turbulence, u0+/u0−, above and below the interface. This study focuses on gas–liquid interfaces so that ρ+/ρ− ≪ 1 and also on where… 
Turbulence dynamics near a turbulent/non-turbulent interface
Abstract The characteristics of the boundary layer separating a turbulence region from an irrotational (or non-turbulent) flow region are investigated using rapid distortion theory (RDT). The
Turbulence and Wave Dynamics Across Gas–Liquid Interfaces
Mechanisms are reviewed here for the distortion of turbulent flows near thin density interfaces and their effects on transfer processes across them. Firstly the results of rapid distortion
Two-fluid confined flow in a cylinder driven by a rotating end wall.
The simulations show that even when there is significant interfacial deformation, both the dynamics and the equilibrium flow are dominated by vortex bending rather than vortex stretching, and for the range of immiscible fluids considered, surface tension effects are significant.
Numerical investigation of shear-flow free-surface turbulence and air entrainment at large Froude and Weber numbers
We investigate two-phase free-surface turbulence (FST) associated with an underlying shear flow under the condition of strong turbulence (SFST) characterized by large Froude ( $Fr$ ) and Weber ( $We$
Oscillating grid turbulence and its influence on gas liquid mass transfer and mixing in non-Newtonian media
The study of turbulence induced mass transfer at the interface between a gas and a liquid is of great interest in many environmental phenomena and industrial processes. Even though this issue has
Turbulent structure of air flow over wind-induced gravity waves
This is the second paper in a group of three that reports the systematic measurements of wind-generated water waves in a wind tunnel experiment. Here, the structure of the boundary layer on the air
Experimental study on oscillating grid turbulence and free surface fluctuation
This paper analyses the interaction between the turbulence and free surface. The phenomenon takes place in many natural flows and industrial processes. In the present experiments, turbulence is
Nonlinear coupling of interfacial instabilities with resonant wave interactions in horizontal two-fluid plane Couette–Poiseuille flows: numerical and physical observations
We investigate mechanisms governing the initial growth and nonlinear evolution of interfacial waves in horizontal two-fluid plane Couette–Poiseuille flows. Nonlinear coupling of the Kelvin–Helmholtz


Turbulence, waves and mixing at shear-free density interfaces. Part 1. A theoretical model
This paper presents a theoretical model of turbulence and mixing at a shear-free stable density interface. In one case (single-sided stirring) the interface separates a layer of fluid of density ρ in
Direct numerical simulation of near-interface turbulence in coupled gas-liquid flow
Turbulence structures near the interface between two flowing fluids have been resolved by direct numerical simulation. As a first step the interface has been kept flat, corresponding closely to the
Turbulence structure in thermal convection and shear-free boundary layers
This paper is a study of turbulence near rigid surfaces, in the absence of any mean shear. Different sources of turbulence are considered, including thermal convection and grid turbulence. It is
Direct numerical simulation of turbulence in a sheared air–water flow with a deformable interface
Direct numerical simulation has been performed to explore the turbulence near a freely deformable interface in a countercurrent air–water flow, at a shear Reynolds number $\Re_{\star}=171$. The
Velocity fluctuations near an interface between a turbulent region and a stably stratified layer
Velocity fluctuations are calculated near an interface between a turbulent region and a stably stratified layer, and in the absence of mean shear. Based on the observation that the energy dissipation
An Analysis of Turbulent Motions In and Around a Differentially Forced Density Interface
Abstract:The Rapid-Distortion-Theory-based analysis proposed by Fernando and Hunt [1] is extended to study the nature of turbulence in and around a density interface sandwiched between turbulent
On the initiation of surface waves by turbulent shear flow
A numerical study of the evolution and structure of a turbulent shear layer under a free surface
Results from direct numerical simulations of an unsteady turbulent shear layer with a free surface are presented. The emphasis is on the interaction dynamics of the free surface with the coherent
Statistical structure of high-Reynolds-number turbulence close to the free surface of an open-channel flow
Statistical characteristics of turbulence in the near-surface region of a steady open- channel flow are examined using new data obtained in a high-Reynolds-number large-eddy simulation using a
The dynamics of strong turbulence at free surfaces. Part 2. Free-surface boundary conditions
Strong turbulence at a water–air free surface can lead to splashing and a disconnected surface as in a breaking wave. Averaging to obtain boundary conditions for such flows first requires equations