An experimental investigation of the collective oscillations of bubble plumes entrained by breaking waves

1994 ◽  
Vol 95 (3) ◽  
pp. 1329-1343 ◽  
Author(s):  
M. R. Loewen ◽  
W. K. Melville
Keyword(s):  
Experimental Investigation ◽  
Breaking Waves ◽  
Bubble Plumes ◽  
Collective Oscillations

scholarly journals Ocean bubbles under high wind conditions. Part 1: Bubble distribution and development

2021 ◽  
Author(s):  
Helen Czerski ◽  
Ian M. Brooks ◽  
Steve Gunn ◽  
Robin Pascal ◽  
Adrian Matei ◽  
...  
Keyword(s):  
Void Fraction ◽  
Breaking Waves ◽  
Surface Flow ◽  
Stokes Drift ◽  
Gas Transfer ◽  
Langmuir Circulation ◽  
Near Surface ◽  
Wind Speeds ◽  
Void Fractions ◽  
Bubble Plumes

Abstract. The bubbles generated by breaking waves are of considerable scientific interest due to their influence on air-sea gas transfer, aerosol production, and upper ocean optics and acoustics. However, a detailed understanding of the processes creating deeper bubble plumes (extending 2–10 metres below the ocean surface) and their significance for air-sea gas exchange is still lacking. Here, we present bubble measurements from the HiWinGS expedition in the North Atlantic in 2013, collected during several storms with wind speeds of 10–27 m s−1. A suite of instruments was used to measure bubbles from a self-orienting free-floating spar buoy: a specialised bubble camera, acoustical resonators, and an upward-pointing sonar. The focus in this paper is on bubble void fractions and plume structure. The results are consistent with the presence of a heterogeneous shallow bubble layer occupying the top 1–2 m of the ocean which is regularly replenished by breaking waves, and deeper plumes which are only formed from the shallow layer at the convergence zones of Langmuir circulation. These advection events are not directly connected to surface breaking. The void fraction distributions at 2 m depth show a sharp cut-off at a void fraction of 10−4.5 even in the highest winds, implying the existence of mechanisms limiting the void fractions close to the surface. Below wind speeds of 16 m s−1 or RHw = 2 × 106, the probability distribution of void fraction at 2 m depth is very similar in all conditions, but increases significantly above either threshold. Void fractions are significantly different during periods of rising and falling winds, but there is no distinction with wave age. There is a complex near-surface flow structure due to Langmuir circulation, Stokes drift, and wind-induced current shear which influences the spatial distribution of bubbles within the top few metres. We do not see evidence for slow bubble dissolution as bubbles are carried downwards, implying that collapse is the more likely termination process. We conclude that the shallow and deeper bubble layers need to be studied simultaneously to link them to the 3D flow patterns in the top few metres of the ocean. Many open questions remain about the extent to which deep bubble plumes contribute to air-sea gas transfer. A companion paper (Czerski, 2021) addresses the observed bubble size distributions and the processes responsible for them.

scholarly journals Breaking waves and bubble plumes

1993 ◽  
Vol 93 (4) ◽  
pp. 2379-2379
Author(s):  
Peter H. Dahl ◽  
Andrew T. Jessup
Keyword(s):  
Breaking Waves ◽  
Bubble Plumes

A CFD Investigation on the Effect of the Air Entrainment in Breaking Wave Impacts on a Mono-Pile

2017 ◽  
Author(s):  
Pietro D. Tomaselli ◽  
Erik Damgaard Christensen
Keyword(s):  
Experimental Investigation ◽  
Circular Cylinder ◽  
Air Entrainment ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Breaking Wave ◽  
Line Force ◽  
Entrainment Process ◽  
The Impact

In impacts of breaking waves on offshore structures, it is still not well-known how the air entrainment phenomenon affects the exerted loads. In this paper, a developed CFD solver capable of simulating the air entrainment process was employed to reproduce an experimental investigation on the impact of a spilling wave against a circular cylinder. The exerted in-line force was computed with and without the inclusion of dispersed bubbles. Results showed that the magnitude of the computed force was affected when the entrainment of bubbles was simulated.

scholarly journals EXPERIMENTAL INVESTIGATION OP SHOCK PRESSURES AGAINST BREAKWATERS

1968 ◽  
Vol 1 (11) ◽  
pp. 62 ◽  
Author(s):  
Gustaf Richert
Keyword(s):  
Experimental Investigation ◽  
Wave Front ◽  
Water Depth ◽  
Test Procedure ◽  
Breaking Waves ◽  
Pressure Variation ◽  
Shock Pressure ◽  
Compression And Expansion ◽  
Air Cushion ◽  
Special Respect

This paper describes an experimental investigation of shock pressures against breakwaters caused by "breaking waves. The study only considers shocks of a compressive type, which occur if the wave front is formed in such a way that an air cushion is entrapped between the wave and the wall. In this case the compression and expansion of the air cushion plays an important role m the pressure variation. Only waves preceded by non-breaking waves were used. For different combinations of bottom geometry and water depth the occurrence of shock pressures of different magnitudes was studied varying the wave height and the wave period. For some interesting combinations of bottom geometry and wave dimensions a series of tests were made to investigate the distribution over the wall of shock pressure and of shock impulse. The results, presented m diagrams and tables, have been commented on and analysed with special respect to the chosen test procedure.

A Novel Method for Generating Continuously Surfable Waves: Comparison of Predictions With Experimental Results

2011 ◽  
Author(s):  
Steven A. Schmied ◽  
Jonathan R. Binns ◽  
Martin R. Renilson ◽  
Giles A. Thomas ◽  
Gregor J. Macfarlane ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Experimental Investigation ◽  
Wave Breaking ◽  
Breaking Waves ◽  
Experimental Results ◽  
Pressure Source ◽  
Towing Tank ◽  
Novel Method ◽  
The Waves

In this paper, a novel idea to produce continuous breaking waves is discussed, whereby a pressure source is rotated within an annular wave pool. The concept is that the inner ring of the annulus has a sloping bathymetry to induce wave breaking from the wake of the pressure source. In order to refine the technique, work is being conducted to better understand the mechanics of surfable waves generated by moving pressure sources in restricted water. This paper reports on the first stage of an experimental investigation of a novel method for generating continuously surfable waves utilising a moving pressure source. The aim was to measure and assess the waves generated by two parabolic pressure sources and a wavedozer [1] for their suitability for future development of continuous breaking surfable waves. The tests were conducted at the Australian Maritime College (AMC), University of Tasmania (UTas) 100 metre long towing tank. The experimental results as variations in wave height (H) divided by water depth (h) as functions of depth Froude number (Frh) and h, together with predictions from both methods, are presented in this paper. Finally, measures of the wave making energy efficiency of each pressure source, and the surfable quality of the waves generated by it, were developed and are presented.

Comprehensive experimental investigation of the hydrodynamics of large-scale, 3D, oscillating bubble plumes

2006 ◽  
Vol 32 (10-11) ◽  
pp. 1160-1181 ◽  
Author(s):  
M. Simiano ◽  
R. Zboray ◽  
F. de Cachard ◽  
D. Lakehal ◽  
G. Yadigaroglu
Keyword(s):  
Experimental Investigation ◽  
Large Scale ◽  
Bubble Plumes
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