Scattering from impedance gratings and surface wave formation

2002 ◽  
Vol 111 (5) ◽  
pp. 1996 ◽  
Author(s):  
Wenhao Zhu ◽  
Michael R. Stinson ◽  
Gilles A. Daigle
Keyword(s):  
Surface Wave ◽  
Wave Formation

scholarly journals Dynamics of Bubble Motion and Gas-Liquid Interfacial Phenomena

2003 ◽  
Author(s):  
Katsumi Tsuchiya
Keyword(s):  
Mass Transfer ◽  
Surface Wave ◽  
High Speed ◽  
Bubble Surface ◽  
Liquid Interface ◽  
Oscillatory Motion ◽  
Wave Formation ◽  
High Speed Imaging ◽  
Vertical Projection ◽  
Near Surface

Two aspects of the dynamics associated with oscillating bubbles are discussed in this paper: oscillatory motion of bubble itself and bubble-surface wave. The primary issue here is whether it is the case that the surface wave occurs in sychronization with the bubble’s oscillatory motion. The dynamic process of wave formation and propagation along the surface of an oscillating bubble is studied based on high-speed imaging, through which the wave characteristics such as wavelength and phase/propagation speed are evaluated as mostly the vertical projection of rather regularly generated bubble-surface ripples. The bubble oscillating motion is characterized quantitatively by the bubble-gyration (or edge-rotation) frequency, diameter and velocity. In addition, dynamics of mass transfer across gas–liquid interface in a gas-dispersed (continuous liquid) system are examined via high-sensitivity, high-speed imaging. The dispersive dynamics of the dissolved component from the gas into the liquid phase are visualized using laser-induced fluorescence (LIF) with pH-sensitive pyrene (HPTS) for both a single and multi-bubble systems. The coupling between these dynamics of surface/interfacial flow and mass transfer is attempted towards better understanding of such complex phenomena prevailing in the vicinity of the fluctuating gas–liquid interface. Enhancement of the mass transfer is found to be associated with the (nonlinear) wave formation, influence of which could be included in modeling the mass-transfer coefficient, apart from an physical account of the near-surface concentration gradient. Due to significant bubble–bubble interactions in a multi-bubble system, the dispersive pattern of low-pH region arising from gas dissolution becomes extremely complex; the visual estimate of time variation in fluorescence level is then mainly made over a fixed space in the gas–liquid flow system.

Mass transfer enhancement due to surface wave formation at a horizontal gas–liquid interface

2000 ◽  
Vol 55 (23) ◽  
pp. 5851-5856 ◽  
Author(s):  
G. Vázquez-Uña ◽  
F. Chenlo-Romero ◽  
M. Sánchez-Barral ◽  
V. Pérez-Muñuzuri
Keyword(s):  
Mass Transfer ◽  
Surface Wave ◽  
Liquid Interface ◽  
Wave Formation ◽  
Transfer Enhancement ◽  
Mass Transfer Enhancement

Surface wave formation at an impedance discontinuity

1997 ◽  
Vol 102 (6) ◽  
pp. 3269-3275 ◽  
Author(s):  
Michael R. Stinson ◽  
Gilles A. Daigle
Keyword(s):  
Surface Wave ◽  
Wave Formation ◽  
Impedance Discontinuity

Exit-surface wave reconstruction using a focal series

1992 ◽  
Vol 50 (2) ◽  
pp. 988-989
Author(s):  
W.J. de Ruijter ◽  
M.R. McCartney ◽  
David J. Smith ◽  
J.K. Weiss
Keyword(s):  
Surface Wave ◽  
Spherical Aberration ◽  
Data Extraction ◽  
High Sensitivity ◽  
Geometric Distortion ◽  
Variation Method ◽  
Objective Lens ◽  
Immediate Reconstruction ◽  
Exit Surface ◽  
Electron Microscopes

Further advances in resolution enhancement of transmission electron microscopes can be expected from digital processing of image data recorded with slow-scan CCD cameras. Image recording with these new cameras is essential because of their high sensitivity, extreme linearity and negligible geometric distortion. Furthermore, digital image acquisition allows for on-line processing which yields virtually immediate reconstruction results. At present, the most promising techniques for exit-surface wave reconstruction are electron holography and the recently proposed focal variation method. The latter method is based on image processing applied to a series of images recorded at equally spaced defocus.Exit-surface wave reconstruction using the focal variation method as proposed by Van Dyck and Op de Beeck proceeds in two stages. First, the complex image wave is retrieved by data extraction from a parabola situated in three-dimensional Fourier space. Then the objective lens spherical aberration, astigmatism and defocus are corrected by simply dividing the image wave by the wave aberration function calculated with the appropriate objective lens aberration coefficients which yields the exit-surface wave.

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