Experimental Study of Three-Dimensional Wave Formation from a Solitary Two-Dimensional Wave on Vertically Falling Liquid Films

2020 ◽  
Vol 61 (3) ◽  
pp. 5-10
Author(s):  
A.V. Bobylev ◽  
V.V. Guzanov ◽  
A.Z. Kvon ◽  
S.M. Kharlamov ◽  
D.M. Markovich
Keyword(s):  
Experimental Study ◽  
Three Dimensional ◽  
Liquid Films ◽  
Wave Formation ◽  
Two Dimensional ◽  
Falling Liquid Films ◽  
Dimensional Wave

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.

scholarly journals Волновая структура пленок жидкости при переходе к турбулентному режиму течения

2019 ◽  
Vol 45 (15) ◽  
pp. 10
Author(s):  
А.В. Бобылев ◽  
С.М. Харламов ◽  
В.В. Гузанов ◽  
А.З. Квон ◽  
Д.М. Маркович
Keyword(s):  
Experimental Study ◽  
Flow Regime ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Liquid Films ◽  
Diagnostic Methods ◽  
Structural Elements ◽  
Optical Diagnostic ◽  
Turbulent Flow Regime ◽  
Falling Liquid Films

The paper presents the results of an experimental study of waves on falling liquid films in the range of Reynolds numbers 80 < Re < 420. Experiments were conducted using field optical diagnostic methods with high spatial and temporal resolution. On the humps of large three-dimensional waves, a generation of capillary ripples with a small wavelength was observed. As noted in the literature, it is in these areas of three-dimensional waves so-called “turbulence spots” are observed, the appearance of which is associated with a transition to a turbulent flow regime. Also long-lived rounded dimples were observed with characteristic transverse dimensions of 1–3 mm, which are formed in the interaction region of capillary precursors and then travel as independent structural elements of the flow.

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

Two- and three-dimensional locomotion of the nematode Nippostrongylus brasiliensis

Parasitology ◽  
1990 ◽  
Vol 101 (2) ◽  
pp. 301-308 ◽  
Author(s):  
D. L. Lee ◽  
W. D. Biggs
Keyword(s):  
Sodium Alginate ◽  
Intestinal Mucosa ◽  
Three Dimensional ◽  
Viscous Medium ◽  
Nippostrongylus Brasiliensis ◽  
Two Dimensional ◽  
Immune Rejection ◽  
Forward Movement ◽  
Helical Wave ◽  
Dimensional Wave

Locomotion of adult Nippostrongylus brasiliensis has been studied in saline, in 0.6% agar, in sodium alginate of different viscosities and amongst sand grains in these media. In saline the nematode formed two-dimensional waves but there was little forward progression. Amongst sand grains in saline the nematode moved forwards by thrusting against sand grains, but thigmokinetic behaviour later resulted in quiescence. In 0.6% agar and in alginates of weak viscosity the nematode produced two-dimensional waves and sometimes a three-dimensional helical wave which resulted in forward movement. The formation of three-dimensional waves and the distance travelled increased with increasing viscosity up to 4% sodium alginate and also amongst sand gains in these media. In 8% sodium alginate the nematode became coiled like a spring but remained almost stationary. The three-dimensional wave is formed with torsion and obtains thrust from the viscous medium. In the intestine of the host thrust will be obtained from the mucus and villi of the intestinal mucosa. The ability of this nematode to move by two-and three-dimensional undulatory propulsion is probably related to its complex ridged cuticle. Attention is drawn to the role that increased viscosity of mucus may play in entrapping nematodes during their immune rejection.

scholarly journals Optimization of the multidimensional signal interpolator in a lower dimensional space

2019 ◽  
Vol 43 (4) ◽  
pp. 653-660 ◽  
Author(s):  
M.V. Gashnikov
Keyword(s):  
Experimental Study ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Multidimensional Signals ◽  
Multidimensional Signal ◽  
Signal Sample ◽  
Lower Dimensional Space ◽  
Lower Dimensional ◽  
Selection Of

Adaptive multidimensional signal interpolators are developed. These interpolators take into account the presence and direction of boundaries of flat signal regions in each local neighborhood based on the automatic selection of the interpolating function for each signal sample. The selection of the interpolating function is performed by a parameterized rule, which is optimized in a parametric lower dimensional space. The dimension reduction is performed using rank filtering of local differences in the neighborhood of each signal sample. The interpolating functions of adaptive interpolators are written for the multidimensional, three-dimensional and two-dimensional cases. The use of adaptive interpolators in the problem of compression of multidimensional signals is also considered. Results of an experimental study of adaptive interpolators for real multidimensional signals of various types are presented.

Thermal Entry in Falling Liquid Films at High Reynolds Numbers

2011 ◽  
Vol 6 (4) ◽  
pp. 51-54
Author(s):  
Evgeny Chinnov ◽  
Sergey Abdurakipov
Keyword(s):  
Experimental Study ◽  
Reynolds Numbers ◽  
Liquid Films ◽  
Field Methods ◽  
Entry Length ◽  
Temperature Measuring ◽  
Strong Wave ◽  
High Reynolds Numbers ◽  
High Reynolds ◽  
Falling Liquid Films

An experimental study of thermal entry length in falling liquid films at high Reynolds numbers was performed with the use of field methods for thickness and temperature measuring. It was shown that the combination of the strong wave and thermocapillary effects leads to a significant decrease of thermal entry length

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