Sound generation and air entrainment by breaking waves in the surf zone

1997 ◽  
Vol 102 (5) ◽  
pp. 2671-2689 ◽  
Author(s):  
Grant B. Deane
Keyword(s):  
Surf Zone ◽  
Air Entrainment ◽  
Breaking Waves ◽  
Sound Generation

scholarly journals NUMERICAL SIMULATIONS OF SPILLING BREAKING WAVES

2011 ◽  
Vol 1 (32) ◽  
pp. 11
Author(s):  
Pierre Lubin ◽  
Stéphane Glockner ◽  
Olivier Kimmoun ◽  
Hubert Branger
Keyword(s):  
Surf Zone ◽  
Early Stage ◽  
Air Entrainment ◽  
Breaking Waves ◽  
Qualitative Comparison ◽  
Vorticity Generation ◽  
Mesh Grid ◽  
The Waves ◽  
Plunging Breaker ◽  
White Foam

Numerical simulation of spilling breaking waves is still a very challenging aim to achieve since small interface deformations, air entrainment and vorticity generation are involved during the early stage of the breaking of the wave. High mesh grid resolutions and appropriate numerical methods are required to capture accurately the length scales of the complex mechanisms responsible for the start of the breaking (small plunging jet, white foam, etc.). Numerical works usually showed better agreements when simulating plunging breaking waves than the spilling case compared with available experimental data. Kimmoun and Branger (2007) recently experimented surf-zone breaking waves. Detailed pictures showed a short spilling event occurred at the crest of the waves, before degenerating into strong plunging breaker. This work is devoted to the qualitative comparison of our numerical results with the experimental observations, as we will focus on capturing and describing the spilling phase experimented.

scholarly journals The Accelerations of a Wave Measurement Buoy Impacted by Breaking Waves in the Surf Zone

2021 ◽  
Vol 9 (2) ◽  
pp. 214
Author(s):  
Adam C. Brown ◽  
Robert K. Paasch
Keyword(s):  
Inertial Measurement Unit ◽  
Surf Zone ◽  
Spherical Wave ◽  
Breaking Waves ◽  
Measurement Unit ◽  
High Fidelity ◽  
Wave Measurement ◽  
Near Shore ◽  
Shoaling Waves ◽  
Multiple Deployments

A spherical wave measurement buoy capable of detecting breaking waves has been designed and built. The buoy is 16 inches in diameter and houses a 9 degree of freedom inertial measurement unit (IMU). The orientation and acceleration of the buoy is continuously logged at frequencies up to 200 Hz providing a high fidelity description of the motion of the buoy as it is impacted by breaking waves. The buoy was deployed several times throughout the winter of 2013–2014. Both moored and free-drifting data were acquired in near-shore shoaling waves off the coast of Newport, OR. Almost 200 breaking waves of varying type and intensity were measured over the course of multiple deployments. The characteristic signature of spilling and plunging breakers was identified in the IMU data.

scholarly journals Development and Validation of Quasi-Eulerian Mean Three-Dimensional Equations of Motion Using the Generalized Lagrangian Mean Method

2021 ◽  
Vol 9 (1) ◽  
pp. 76
Author(s):  
Duoc Nguyen ◽  
Niels Jacobsen ◽  
Dano Roelvink
Keyword(s):  
Surface Waves ◽  
Deep Water ◽  
Surf Zone ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Breaking Waves ◽  
Successful Implementation ◽  
Random Waves ◽  
Mean Motion ◽  
Generalized Lagrangian

This study aims at developing a new set of equations of mean motion in the presence of surface waves, which is practically applicable from deep water to the coastal zone, estuaries, and outflow areas. The generalized Lagrangian mean (GLM) method is employed to derive a set of quasi-Eulerian mean three-dimensional equations of motion, where effects of the waves are included through source terms. The obtained equations are expressed to the second-order of wave amplitude. Whereas the classical Eulerian-mean equations of motion are only applicable below the wave trough, the new equations are valid until the mean water surface even in the presence of finite-amplitude surface waves. A two-dimensional numerical model (2DV model) is developed to validate the new set of equations of motion. The 2DV model passes the test of steady monochromatic waves propagating over a slope without dissipation (adiabatic condition). This is a primary test for equations of mean motion with a known analytical solution. In addition to this, experimental data for the interaction between random waves and a mean current in both non-breaking and breaking waves are employed to validate the 2DV model. As shown by this successful implementation and validation, the implementation of these equations in any 3D model code is straightforward and may be expected to provide consistent results from deep water to the surf zone, under both weak and strong ambient currents.

Distributions of void fraction under breaking waves in the surf zone

2005 ◽  
Vol 32 (14-15) ◽  
pp. 1829-1840 ◽  
Author(s):  
Ashabul Hoque ◽  
Shin-ichi Aoki
Keyword(s):  
Void Fraction ◽  
Surf Zone ◽  
Breaking Waves

scholarly journals LABORATORY EXPERIMENTS ON THE INFLUENCE OF WIND ON NEARSHORE WAVE BREAKING

1988 ◽  
Vol 1 (21) ◽  
pp. 46
Author(s):  
Scott L. Douglass ◽  
J. Richard Weggel
Keyword(s):  
Wind Direction ◽  
Wave Breaking ◽  
Laboratory Experiments ◽  
Surf Zone ◽  
Breaking Waves ◽  
Wave Tank ◽  
Zone Width

The influence of wind on nearshore breaking waves was investigated in a laboratory wave tank. Breaker location, geometry, and type depended upon the wind acting on the wave as it broke. Onshore winds tended to cause waves to break earlier, in deeper water, and to spill: offshore winds tended to cause waves to break later, in shallower water, and to plunge. A change in wind direction from offshore to onshore increased the surf zone width by up to 100%. Wind's effect was greatest for waves which were near the transition between breaker types in the absence of wind. For onshore winds, it was observed that microscale breaking can initiate spilling breaking by providing a perturbation on the crest of the underlying wave as it shoals.

Development of Rigid Inflatable Boats for U.S. Navy Shipboard Use

1985 ◽  
Vol 22 (03) ◽  
pp. 211-218
Author(s):  
David W. Amick ◽  
Robert Hamilton ◽  
Curtis E. Shields
Keyword(s):  
High Performance ◽  
Surf Zone ◽  
Single Point ◽  
Development Program ◽  
Feasibility Studies ◽  
Breaking Waves ◽  
Coast Guard ◽  
Superior Performance ◽  
Concept Evaluation ◽  
The U.S

The Rigid Inflatable Boat (RIB) was originally developed as a gasoline outboard powered craft for surf zone rescue use by the Royal National Lifeboat Institution in the United Kingdom. The objectives were to provide a craft with extremely good stability characteristics to operate in steep onshore breaking waves without capsizing, and to improve the safety of operations alongside other vessels. Open ocean rescue and boarding applications were of interest to the U.S. Coast Guard because of the inherent stability and alongside safety of the RIB. Subsequent feasibility studies by the U.S. Navy indicated that the RIB would be superior in performance to the present 26-ft motor whaleboat, and could also reduce topside weight. The Navy opted for diesel inboard power for the RIB's designated to be carried aboard combatant ships. A diesel-powered RIB was procured for concept evaluation by the U.S. Navy, and has undergone a series of trials and tests to establish smooth-and rough-water performance characteristics. The data acquired confirmed the theoretical performance predicted during the feasibility studies. This first RIB was deployed on a U.S. Navy DDG-993 Class ship utilizing an existing single-point davit. During that deployment, the RIB was launched and retrieved successfully at ship's speeds up to 12 knots. Early indications are that this development program will result in a new ship's boat and an accompanying davit system which will provide the Fleet with a safe, high-performance craft which will greatly enhance operational capability and safety, and substantially reduce topside weight. The enthusiasm of test and Fleet personnel who have operated the RIB attests to its superior performance and to a high degree of probability for success of the program.

scholarly journals SURF ZONE MEASUREMENTS OF SUSPENDED SEDIMENT

1978 ◽  
Vol 1 (16) ◽  
pp. 104 ◽  
Author(s):  
Timothy W. Kana
Keyword(s):  
South Carolina ◽  
Suspended Sediment ◽  
Surf Zone ◽  
Sediment Concentration ◽  
Breaking Waves ◽  
Bulk Water ◽  
Scatter Plots ◽  
Water Volumes ◽  
Spilling Breakers

Suspended sediment concentration was measured in approximately 250 breaking waves on undeveloped beaches near Price Inlet, South Carolina, U.S.A., using portable in situ bulk water samplers. As many as 10 instantaneous 2-liter water volumes were obtained in each wave for a total of 1500 samples. Concentrations of suspended sediment were determined at fixed intervals of 10, 30, 60 and 100 cm above the bed for various surf zone positions relative to the breakpoint. The majority of waves sampled during 22 days in June and July, 1977 were relatively long crested, smooth, spilling to plunging in form, with breaker heights ranging from 20 to 150 cm. Surf zone process variables measured included breaker height and depth, breaker type, wave period, surface longshore current velocity, wind velocity and direction. Scatter plots of mean concentration against various process parameters indicate the amount of sediment entrained in breaking waves is primarily a function of elevation above the bed, breaker type, breaker height and distance from the breakpoint. Concentration ranged over 3 orders of magnitude up to 10 gm/1, but varied less than 1 order for samples collected under similar conditions with regard to elevation and breaker type. Plunging breakers generally entrain 1 order more sediment than spilling breakers equal in height. Despite considerable scatter, these data indicate concentration decreases with increasing wave height for waves 50 to 150 cm high, suggesting that small waves can be important in the transport of sand on gently-sloping open coasts.

scholarly journals Wake behind a three-dimensional dry transom stern. Part 1. Flow structure and large-scale air entrainment

2019 ◽  
Vol 875 ◽  
pp. 854-883 ◽  
Author(s):  
Kelli Hendrickson ◽  
Gabriel D. Weymouth ◽  
Xiangming Yu ◽  
Dick K.-P. Yue
Keyword(s):  
Froude Number ◽  
Flow Structure ◽  
Large Scale ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Breaking Waves ◽  
Variable Density ◽  
Entrainment Rate ◽  
Two Phase ◽  
Density Spectrum

We present high-resolution implicit large eddy simulation (iLES) of the turbulent air-entraining flow in the wake of three-dimensional rectangular dry transom sterns with varying speeds and half-beam-to-draft ratios $B/D$. We employ two-phase (air/water), time-dependent simulations utilizing conservative volume-of-fluid (cVOF) and boundary data immersion (BDIM) methods to obtain the flow structure and large-scale air entrainment in the wake. We confirm that the convergent-corner-wave region that forms immediately aft of the stern wake is ballistic, thus predictable only by the speed and (rectangular) geometry of the ship. We show that the flow structure in the air–water mixed region contains a shear layer with a streamwise jet and secondary vortex structures due to the presence of the quasi-steady, three-dimensional breaking waves. We apply a Lagrangian cavity identification technique to quantify the air entrainment in the wake and show that the strongest entrainment is where wave breaking occurs. We identify an inverse dependence of the maximum average void fraction and total volume entrained with $B/D$. We determine that the average surface entrainment rate initially peaks at a location that scales with draft Froude number and that the normalized average air cavity density spectrum has a consistent value providing there is active air entrainment. A small parametric study of the rectangular geometry and stern speed establishes and confirms the scaling of the interface characteristics with draft Froude number and geometry. In Part 2 (Hendrikson & Yue, J. Fluid Mech., vol. 875, 2019, pp. 884–913) we examine the incompressible highly variable density turbulence characteristics and turbulence closure modelling.

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