The transition from two-dimensional to three-dimensional waves in falling liquid films: Wave patterns and transverse redistribution of local flow rates

2015 ◽  
Vol 27 (11) ◽  
pp. 114106 ◽  
Author(s):  
S. M. Kharlamov ◽  
V. V. Guzanov ◽  
A. V. Bobylev ◽  
S. V. Alekseenko ◽  
D. M. Markovich
Keyword(s):  
Three Dimensional ◽  
Liquid Films ◽  
Two Dimensional ◽  
Local Flow ◽  
Flow Rates ◽  
Wave Patterns ◽  
Falling Liquid Films

Specific features of a transition from the regular two-dimensional to three-dimensional waves on falling liquid films

2012 ◽  
Vol 38 (8) ◽  
pp. 739-742 ◽  
Author(s):  
S. V. Alekseenko ◽  
V. V. Guzanov ◽  
D. M. Markovich ◽  
S. M. Kharlamov
Keyword(s):  
Three Dimensional ◽  
Liquid Films ◽  
Two Dimensional ◽  
Falling Liquid Films

Some aspects of interaction between three-dimensional and two-dimensional waves on vertically falling liquid films

2011 ◽  
Vol 56 (12) ◽  
pp. 614-617
Author(s):  
S. V. Alekseenko ◽  
V. V. Guzanov ◽  
D. M. Markovich ◽  
S. M. Kharlamov
Keyword(s):  
Three Dimensional ◽  
Liquid Films ◽  
Two Dimensional ◽  
Falling Liquid Films

Three-dimensional flow structures in laminar falling liquid films

2014 ◽  
Vol 743 ◽  
pp. 75-123 ◽  
Author(s):  
Georg F. Dietze ◽  
W. Rohlfs ◽  
K. Nährich ◽  
R. Kneer ◽  
B. Scheid
Keyword(s):  
Surface Waves ◽  
Stokes Equations ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Liquid Films ◽  
Capillary Waves ◽  
Flow Structures ◽  
Two Dimensional ◽  
Viscous Forces ◽  
Falling Liquid Films

AbstractFull numerical simulations of the Navier–Stokes equations for four cases of vertically falling liquid films with three-dimensional surface waves have been performed. Flow conditions are based on several previous experimental studies where the streamwise and spanwise wavelengths were imposed, which we exploit by simulating periodic wave segments. The considered flows are laminar but approach conditions at which intermittent wave-induced turbulence has been observed elsewhere. Working liquids range from water to silicone oil and cover a large interval of the Kapitza number ($\textit {Ka}=18\mbox{--}3923$), which relates capillary to viscous forces. Simulations were performed on a supercomputer, using a finite-volume code and the volume of fluid and continuum surface force methods to account for the multiphase nature of the flow. Our results show that surface waves, consisting of large horseshoe-shaped wave humps concentrating most of the liquid and preceded by capillary ripples on a thin residual film, segregate the flow field into two regions: an inertia-dominated one in the large humps, where the local Reynolds number is up to five times larger than its mean value, and a visco-capillary region, where capillary and/or viscous forces dominate. In the inertial region, an intricate structure of different-scale vortices arises, which is more complicated than film thickness variations there suggest. Conversely, the flow in the visco-capillary region of large-$\textit {Ka} $ fluids is entirely governed by the local free-surface curvature through the action of capillary forces, which impose the pressure distribution in the liquid film. This results in flow separation zones underneath the capillary troughs and a spanwise cellular flow pattern in the region of capillary wave interference. In some cases, capillary waves bridge the large horseshoe humps in the spanwise direction, coupling the two aforementioned regions and leading the flow to oscillate between three- and two-dimensional wave patterns. This persists over long times, as we show by simulations with the low-dimensional model of Scheid et al. (J. Fluid Mech., vol. 562, 2006, pp. 183–222) after satisfactory comparison with our direct simulations at short times. The governing mechanism is connected to the bridging capillary waves, which drain liquid from the horseshoe humps, decreasing their amplitude and wave speed and causing them to retract in the streamwise direction. Overall, it is observed that spanwise flow structures (not accounted for in two-dimensional investigations) are particularly complex due to the absence of gravity in this direction.

Heat Transfer and Evaporation of Falling Liquid Films on Surfaces With Advanced Three-Dimensional Periodic Structures: Experiments and Numerical Simulations

2010 ◽  
Author(s):  
Karsten Lo¨ffler ◽  
Hongyi Yu ◽  
Steffen Hardt ◽  
Tatiana Gambaryan-Roisman ◽  
Peter Stephan
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Wall Temperature ◽  
Three Dimensional ◽  
Liquid Films ◽  
Film Rupture ◽  
Reduced Pressure ◽  
Capillary Suction ◽  
Structured Surfaces ◽  
Falling Liquid Films

Thin liquid films are widely used in many technological applications. Heat and mass transfer in falling liquid films can be controlled and enhanced by using walls with advanced three-dimensional topographies that influence the film hydrodynamics, stability and wavy pattern or promote evaporation in a very thin film region. Furthermore, capillary suction on structured surfaces leads to a significant increase of the critical heat flux. In this work, heat transfer in laminar falling water films on heated plates with herringbone structure and with meandering grooves has been studied experimentally for different heat fluxes (up to 24 kW/m2), inclination angles and flow rates under reduced pressure, so that evaporation has a significant impact on heat transfer. The flow patterns and temperature gradients on the liquid-gas interface are visualized by high-speed infrared thermography. The wall temperature distribution is measured with thermocouples. The experimental data are compared with the results of numerical simulations. The predicted effect of micro region evaporation on heat transfer has been confirmed experimentally for the first time for partially wetting films on a plate with meandering grooves. This effect manifests itself in a significant decrease of the local wall temperature after the film rupture and consequent transition from a continuous film flow to rivulet flow regime.

scholarly journals Flow structure in the three dimensional waves on the surface of the vertically falling liquid films

2017 ◽  
Vol 899 ◽  
pp. 062001
Author(s):  
A Z Kvon ◽  
A V Bobylev ◽  
V V Guzanov ◽  
D M Markovich ◽  
S M Kharlamov
Keyword(s):  
Flow Structure ◽  
Three Dimensional ◽  
Liquid Films ◽  
Falling Liquid Films

Extreme solitary waves on falling liquid films

2014 ◽  
Vol 745 ◽  
pp. 564-591 ◽  
Author(s):  
S. Chakraborty ◽  
P.-K. Nguyen ◽  
C. Ruyer-Quil ◽  
V. Bontozoglou
Keyword(s):  
Solitary Waves ◽  
Detailed Comparison ◽  
Liquid Films ◽  
Equation Model ◽  
Local Flow ◽  
Liquid Film Flow ◽  
Wave Models ◽  
Low Dimensional ◽  
Falling Liquid Films ◽  
Wave Properties

AbstractDirect numerical simulation (DNS) of liquid film flow is used to compute fully developed solitary waves and to compare their characteristics with the predictions of low-dimensional models. Emphasis is placed on the regime of high inertia, where available models provide widely differing results. It is found that the parametric dependence of wave properties on inertia is highly non-trivial, and is satisfactorily approximated only by the four-equation model of Ruyer-Quil & Manneville (Eur. Phys. J. B, vol. 15, 2000, pp. 357–369). Detailed comparison of the asymptotic shapes of upstream and downstream tails is performed, and inherent limitations of all long-wave models are revealed. Local flow reversal in front of the main hump, which has been previously discussed in the literature, is shown to occur for an inertia range bounded from below and from above, and the boundaries are interpreted in terms of the capillary origin of the phenomenon. Computational results are reported for the entire range of Froude numbers, providing benchmark data for all wall inclinations.

Sign in / Sign up

Export Citation Format

Share Document