scholarly journals Bubbles generated from wind-steepened breaking waves: 2. Bubble plumes, bubbles, and wave characteristics

2006 ◽  
Vol 111 (C6) ◽  
Author(s):  
Ira Leifer ◽  
Guillemette Caulliez ◽  
Gerrit de Leeuw
Keyword(s):  
Breaking Waves ◽  
Wave Characteristics ◽  
Bubble Plumes

Distribution of Wave Impact Forces From Breaking and Non-Breaking Waves

2009 ◽  
Author(s):  
Anne M. Fullerton ◽  
Thomas C. Fu ◽  
Edward S. Ammeen
Keyword(s):  
Free Surface ◽  
Wave Height ◽  
Breaking Waves ◽  
Qualitative Assessment ◽  
Total Force ◽  
Impact Loads ◽  
Wave Impact ◽  
Data Set ◽  
Wave Characteristics ◽  
Wide Range

Impact loads from waves on vessels and coastal structures are highly complex and may involve wave breaking, making these changes difficult to estimate numerically or empirically. Results from previous experiments have shown a wide range of forces and pressures measured from breaking and non-breaking waves, with no clear trend between wave characteristics and the localized forces and pressures that they generate. In 2008, a canonical breaking wave impact data set was obtained at the Naval Surface Warfare Center, Carderock Division, by measuring the distribution of impact pressures of incident non-breaking and breaking waves on one face of a cube. The effects of wave height, wavelength, face orientation, face angle, and submergence depth were investigated. A limited number of runs were made at low forward speeds, ranging from about 0.5 to 2 knots (0.26 to 1.03 m/s). The measurement cube was outfitted with a removable instrumented plate measuring 1 ft2 (0.09 m2), and the wave heights tested ranged from 8–14 inches (20.3 to 35.6 cm). The instrumented plate had 9 slam panels of varying sizes made from polyvinyl chloride (PVC) and 11 pressure gages; this data was collected at 5 kHz to capture the dynamic response of the gages and panels and fully resolve the shapes of the impacts. A Kistler gage was used to measure the total force averaged over the cube face. A bottom mounted acoustic Doppler current profiler (ADCP) was used to obtain measurements of velocity through the water column to provide incoming velocity boundary conditions. A Light Detecting and Ranging (LiDAR) system was also used above the basin to obtain a surface mapping of the free surface over a distance of approximately 15 feet (4.6 m). Additional point measurements of the free surface were made using acoustic distance sensors. Standard and high-speed video cameras were used to capture a qualitative assessment of the impacts. Impact loads on the plate tend to increase with wave height, as well as with plate inclination toward incoming waves. Further trends of the pressures and forces with wave characteristics, cube orientation, draft and face angle are investigated and presented in this paper, and are also compared with previous test results.

scholarly journals CHARACTERISTICS OF BREAKING WAVES AND ANALYSIS OF SEDIMENT TRANSPORT IN TELUK KENDARI

2018 ◽  
Vol 9 (2) ◽  
pp. 585-596
Author(s):  
Koko Ondara ◽  
Semeidi Husrin
Keyword(s):  
Sediment Transport ◽  
Wind Direction ◽  
High Tide ◽  
Distribution Patterns ◽  
Breaking Waves ◽  
Hydrodynamic Conditions ◽  
Wave Characteristics ◽  
Bay Area ◽  
Tidal Data ◽  
Wave Hindcasting

One of the problems that often occured in the bay area is a sedimentation process that occurred continuously, causing silting. The movement of sediment material in the process of sedimentation is influenced by the movement of the water flow like the tides, winds, currents and waves. The aim of this study was to determine the characteristics of the hydrodynamic conditions, particularly the distribution pattern and the capacity of the sediments in the Kendari Bay with oceanographic modeling approach. Bathymetry data measured at the site of the research conducted in August 2015. The analysis of distribution patterns of sedimentation, sedimentation capacity, wave hindcasting, wind data and tidal data using software, hindcasting results indicate the dominant wind direction coming from the east. Type tides in Kendari Bay is a mixed mainly semiurdunal tides. The concentration of suspended sediment at low tide is greater than at high tide.  Keywords: sediment transport, wave characteristics, Kendari Bay, hydro - dynamics, mike21

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

scholarly journals FORCES INDUCED BY BREAKERS ON PILES

1982 ◽  
Vol 1 (18) ◽  
pp. 102 ◽  
Author(s):  
Robert L. Wiegel
Keyword(s):  
Surf Zone ◽  
Impact Force ◽  
Breaking Waves ◽  
Wave Loading ◽  
Depth Of Penetration ◽  
Wave Characteristics ◽  
Proper Design ◽  
Bottom Depth ◽  
Wave Induced ◽  
Time Information

This paper consists of three parts. The first part presents a method for analyzing the forces exerted by breaking waves on a cirular pile. The force consists of two components, a slowly varying force and a much larger but very short duration quasi-impact force (probably of the order of 1/100 of a second). The second part is concerned with breaker characteristics, with emphasis being given to the few field data that have been measured. The third part consists of a presentation of some available data on surf zone bottom profile variations with time. Information on all three of these parts is needed for the proper design of a pile supported structure in the surf zone. If the bottom along the site of a proposed pier is sand, an estimate of the variability with time of the profile must be made. The effect of bottom depth and configuration on the height of waves moving shoreward, and the effect of this, in turn, on the wave loading is important in the calculations of wave-induced moments about the bottom. The ability of the structure to withstand these horizontal loads depends in part upon the depth of penetration of the piles. If the bottom varies with time, then calculations of wave characteristics and wave-induced loads on the piles should be made for appropriate bottom configurations.

scholarly journals COMPARISON OF MODEL AND OBSERVED NEARSHORE CIRCULATION

1978 ◽  
Vol 1 (16) ◽  
pp. 46 ◽  
Author(s):  
James H. Allender ◽  
John D. Ditmars ◽  
Wyman Harrison ◽  
Robert A. Paddock
Keyword(s):  
Wave Breaking ◽  
Input Data ◽  
Lake Michigan ◽  
Surf Zone ◽  
Breaking Waves ◽  
Wave Characteristics ◽  
Nearshore Circulation ◽  
Water Level Changes ◽  
Local Water ◽  
Offshore Wave

Results from a two-dimensional numerical model for nearshore circulation induced by waves and wind are compared with observations made during two storms at a beach on Lake Michigan. Model-input data include bathymetry, offshore wave characteristics, wind histories, and local water-level changes. The predicted locations of the breaker zone are in rough accord with those observed during the storms. Data for comparison with model results consist of wave and current observations across the surf zone, especially those acquired by using a towed, instrumented sled. The comparisons show that the model often predicts peak currents near the breaker zone quite well, but underestimates the decay of wave height and the strength of longshore currents across the surf zone. Wave breaking on the bar-trough beach structure prevalent in this study apparently is not well represented by the model. An improved breaking criterion, treatment of breaking waves as traveling bores, and inclusion of horizontal mixing of momentum might add to better simulation of surf-zone currents.

scholarly journals LITTORAL DRIFT FORMATION OF SPITS AND TOMBOLOS

2011 ◽  
Vol 1 (5) ◽  
pp. 22
Author(s):  
M. G. Sauvage ◽  
M. G. Vincent
Keyword(s):  
Practical Interest ◽  
Breaking Waves ◽  
Experimental Results ◽  
Wave Steepness ◽  
Littoral Drift ◽  
Wave Characteristics ◽  
Basic Ideas

This paper, entirely devoted to the study of phenomena connected with the evolution of sand banks, is introduced by a rapid survey of a few basic ideas about littoral drift; we point out the fundamental role of wave currents and more particularly of the currents caused by breaking waves. We have attempted to determine the influence on littoral drift of such factors as: the wave characteristics, the wave steepness, the inclination of the wave crests breaking onto the beach, the nature of the beach material. The few experimental results given need to be completed and then compared with figures resulting from observations in nature; it is unfortunate that these latter are difficult and expensive to obtain. After these general remarks on littoral drift, we consider a few aspects of the-development of sand banks such as the birth and evolution of littoral spits and tombolos, both of which are littoral formations presenting an obvious practical interest for the engineer responsible for the construction of ports on sandy coasts.

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