Effect of the liquid–gas interface curvature for a superhydrophobic surface with longitudinal grooves in turbulent flows

2021 ◽  
Vol 33 (7) ◽  
pp. 075116
Author(s):  
Jie Yao ◽  
C. J. Teo
Keyword(s):  
Turbulent Flows ◽  
Superhydrophobic Surface ◽  
Interface Curvature

scholarly journals Flow topologies in bubble-induced turbulence: a direct numerical simulation analysis

2018 ◽  
Vol 857 ◽  
pp. 270-290 ◽  
Author(s):  
Josef Hasslberger ◽  
Markus Klein ◽  
Nilanjan Chakraborty
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Small Scale ◽  
Flow Topology ◽  
Two Phase ◽  
Local Flow ◽  
Interface Curvature

This paper presents a detailed investigation of flow topologies in bubble-induced two-phase turbulence. Two freely moving and deforming air bubbles that have been suspended in liquid water under counterflow conditions have been considered for this analysis. The direct numerical simulation data considered here are based on the one-fluid formulation of the two-phase flow governing equations. To study the development of coherent structures, a local flow topology analysis is performed. Using the invariants of the velocity gradient tensor, all possible small-scale flow structures can be categorized into two nodal and two focal topologies for incompressible turbulent flows. The volume fraction of focal topologies in the gaseous phase is consistently higher than in the surrounding liquid phase. This observation has been argued to be linked to a strong vorticity production at the regions of simultaneous high fluid velocity and high interface curvature. Depending on the regime (steady/laminar or unsteady/turbulent), additional effects related to the density and viscosity jump at the interface influence the behaviour. The analysis also points to a specific term of the vorticity transport equation as being responsible for the induction of vortical motion at the interface. Besides the known mechanisms, this term, related to surface tension and gradients of interface curvature, represents another potential source of turbulence production that lends itself to further investigation.

Film Condensation and Aerosol Deposition in Turbulent Flows with Noncondensable Gases

1997 ◽  
Vol 28 (4-6) ◽  
pp. 277-288
Author(s):  
Leonid I. Zaichik ◽  
Bulat I. Nigmatulin ◽  
Vladimir M. Alipchenkov ◽  
V. A. Belov
Keyword(s):  
Turbulent Flows ◽  
Aerosol Deposition ◽  
Film Condensation ◽  
Noncondensable Gases

Numerical Simulation of Turbulent Flows for Free and Forced Vibrations of Bodies in a Flow

2008 ◽  
Vol 39 (8) ◽  
pp. 661-670
Author(s):  
N. A. Shchur ◽  
D. K. Zaitsev
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flows ◽  
Forced Vibrations ◽  
Free And Forced Vibrations

REYNOLDS ANALOGY IN TURBULENT FLOWS OVER ROUGH WALLS - A DNS INVESTIGATION

2018 ◽  
Author(s):  
Pourya Forooghi ◽  
Franco Magagnato ◽  
Bettina Frohnapfel
Keyword(s):  
Turbulent Flows ◽  
Reynolds Analogy ◽  
Rough Walls
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