The nonlinear interaction of vortex rings with a free surface

1997 ◽  
Vol 13 (2) ◽  
pp. 120-129 ◽  
Author(s):  
Ye Quyuan ◽  
C. K. Chu
Keyword(s):  
Free Surface ◽  
Nonlinear Interaction ◽  
Vortex Rings

Nonlinear interaction between gas bubble and free surface

1996 ◽  
Vol 25 (7) ◽  
pp. 607-628 ◽  
Author(s):  
Q.X. Wang ◽  
K.S. Yeo ◽  
B.C. Khoo ◽  
K.Y. Lam
Keyword(s):  
Free Surface ◽  
Nonlinear Interaction ◽  
Gas Bubble

scholarly journals On the interaction of vortex rings and pairs with a free surface for varying amounts of surface active agent

1989 ◽  
Vol 1 (12) ◽  
pp. 2001-2004 ◽  
Author(s):  
L. P. Bernal ◽  
A. Hirsa ◽  
J. T. Kwon ◽  
W. W. Willmarth
Keyword(s):  
Free Surface ◽  
Surface Active Agent ◽  
Active Agent ◽  
Vortex Rings ◽  
Surface Active

scholarly journals The effect of a parallel free surface upon a submerged shallow synthetic jet

2020 ◽  
Author(s):  
Abhay Kumar ◽  
Ashish Karn
Keyword(s):  
Reynolds Number ◽  
Free Surface ◽  
Vortex Ring ◽  
Water Surface ◽  
Primary Objective ◽  
Synthetic Jet ◽  
Vortex Rings ◽  
Beam Laser ◽  
Jet Trajectory ◽  
Water Depths

The interaction of a submerged shallow synthetic jet with a parallel free surface has gathered substantial interest, owing to its relevance to the operation of marine vehicles viz. ships that move close to the water surface. However, despite exhaustive research on the perturbation on a free surface, very few studies have experimentally investigated the effect of unconfined water surface height on the evolution and propagation of a submerged synthetic jet. This study experimentally investigates a synthetic jet submerged in a quiescent flow at shallow depths ejecting parallel to the free surface, through qualitative analysis and quantitative measurements. The qualitative study includes the visualization of the flow using Plane Laser Induced Fluorescence (PLIF) technique, whereas the velocity measurements are carried out by a five-beam Laser Doppler Velocimetry (LDV) probe. The primary objective of these analysis and measurements is to gain a physical insight into the characteristics of vortex ring in a synthetic jet ejected from a fixed orifice at different water depths and at varying Reynolds number. Our studies indicate that the behavior of the vortex rings drastically changes as the depth of the jet crosses a certain threshold. Although no significant change in the path of synthetic jet is observed beyond a threshold depth in our experiments, the jet trajectory shows an interesting dependence on the Reynolds number based on circulation for shallow water depths. It has been found that in the shallow depths, the vortex ring drifts upwards and interacts with the free surface at lower Reynolds number, whereas for larger Reynolds number, the vortex ring rebounds near the free surface and moves downward. Based on our observations, it can be concluded that the phenomenon of upward/downward flection of vortex rings depends both upon its circulation and water depth.

Nonlinear interaction of internal and surface gravity waves in a two-layer fluid with free surface

2010 ◽  
Vol 168 (4) ◽  
pp. 590-602 ◽  
Author(s):  
I. T. Selezov ◽  
O. V. Avramenko ◽  
Yu. V. Gurtovyi ◽  
V. V. Naradovyi
Keyword(s):  
Free Surface ◽  
Gravity Waves ◽  
Nonlinear Interaction ◽  
Surface Gravity ◽  
Surface Gravity Waves

Generation of vortex rings making use of free-surface waves

2003 ◽  
Vol 2003 (0) ◽  
pp. 81
Author(s):  
Yuji Fukaya ◽  
Taiichi Nagata ◽  
Shinnosuke Obi ◽  
Shigeaki Masuda
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Vortex Rings ◽  
Free Surface Waves

The Nonlinear Interaction and Resonance of Steep Long-Crested Bichromatic Surface Waves in a Numerical Wave Tank

2004 ◽  
Author(s):  
R. E. Baddour ◽  
W. Parsons
Keyword(s):  
Free Surface ◽  
Nonlinear Interaction ◽  
Continuity Condition ◽  
Homogeneous Fluid ◽  
Surface Conditions ◽  
Near Resonance ◽  
Type Boundary ◽  
Order Components ◽  
Nonlinear Free Surface ◽  
Numerical Beach

We are studying numerically the problem of generation and propagation of long-crested gravity waves in a tank containing an incompressible inviscid homogeneous fluid initially at rest with a horizontal free surface of finite extent and of infinite depth. A non-orthogonal curvilinear coordinate system, which follows the free surface is constructed which gives a realistic “continuity condition”, since it tracks the entire fluid domain at all times. A depth profile is assumed and employed to perform a waveform relaxation algorithm to decouple the discrete Laplacian along dimensional lines, thereby reducing its computation over this total fluid domain. In addition, the full nonlinear kinematic and dynamic free surface conditions are utilized in the algorithm. A bichromatic deterministic wave maker using a Dirichlet type boundary condition and a suitably tuned numerical beach is utilized. This paper pays special attention to satisfying the full nonlinear free surface conditions and presents the nonlinear interaction of the higher order components, especially near resonance.

Nonlinear interaction of wind-driven oblique surface waves and parametric growth of lower frequency modes

2012 ◽  
Vol 707 ◽  
pp. 150-190
Author(s):  
Sang Soo Lee
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Nonlinear Interaction ◽  
Critical Layer ◽  
Mode Interaction ◽  
Secondary Wave ◽  
Primary Wave ◽  
Nonlinear Growth ◽  
Free Surface Waves ◽  
Difference Mode

AbstractNonlinear interactions between free-surface waves of the same wave speed and wind are studied by extending the linear resonant theory of Miles (J. Fluid Mech., vol. 3, 1957, pp. 185–204). A nonlinear interaction can occur when the steepness of a primary three-dimensional wave, which propagates obliquely to the wind direction, becomes of the order of the cube of the density ratio of air to water. If a secondary wave of smaller amplitude is also an oblique wave, the nonlinear critical-layer interaction between the primary and secondary fluctuations in air generates a difference mode whose wavenumbers are equal to the differences between the primary and secondary values. In addition, the nonlinear interaction in the critical layer between the primary and difference modes induces a parametric-growth effect on the secondary surface wave, if the frequency of the primary wave is higher than that of the secondary wave. The primary wave remains linear during this ‘$2+ 1$ mode critical-layer interaction’ stage between two free-surface waves and a nonlinearly generated mode. The evolution of the secondary-wave amplitude is governed by an integro-differential equation and that of the difference mode is determined by an integral equation. Both inviscid and viscous numerical results show that the nonlinear growth rates become much larger than the linear growth rates. Effect of viscosity is shown to delay the onset of the nonlinear growth. The growth of the secondary and difference modes is more effectively enhanced when the signs of propagation angles of the primary and secondary waves are opposite than when they are equal. The $2+ 1$ mode interaction can occur when wave steepnesses are very small. The nonlinear interaction is entirely confined to a thin critical layer, and the perturbations outside the critical layer are governed by linear equations. It is shown that the initial nonlinear growth of a free-surface wave could be governed by a mode–mode interaction in air.

scholarly journals Turbulent Vortex Ring/Free Surface Interaction

1995 ◽  
Vol 117 (3) ◽  
pp. 374-381 ◽  
Author(s):  
A. Weigand ◽  
M. Gharib
Keyword(s):  
Free Surface ◽  
Vortex Ring ◽  
Surface Interaction ◽  
Vortex Rings ◽  
Small Scale ◽  
Turbulent Vortex ◽  
Turbulent Transition ◽  
Vortex Loops ◽  
Scale Structures ◽  
Small Scale Structures

The interaction of turbulent vortex rings that approach a clean water surface under various angles is experimentally investigated. The temporal evolution of the vortex rings with an initial Reynolds number of Re0 = 7500 is characterized by the laminar/turbulent transition and asymptotic relaminarization of the flow. Using the shadowgraph technique, two major flow cases were identified as a result of the vortex-ring/free-surface interaction: a trifurcation case that results from the interaction during the transition stage, and a bifurcation case that evolves during the fully-developed turbulent stage. In contrast to the laminar interaction, the turbulent bifurcation pattern is characterized by the reconnection and mutual interaction of many small-scale structures. Simultaneous digital particle image velocimetry (DPIV) and shadowgraph measurements reveal that the evolution of the small-scale structures at the free surface is strongly dominated by the bifurcation pattern, which in turn is a consequence of the persisting laminar sublayer in the core regions of the reconnected turbulent vortex loops.

Electron escape from negatively charged vortex rings incident on the free surface of He II

1972 ◽  
Vol 42 (3) ◽  
pp. 267-268 ◽  
Author(s):  
R.P. Mitchell ◽  
G.W. Rayfield
Keyword(s):  
Free Surface ◽  
Vortex Rings ◽  
Electron Escape
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