scholarly journals THE INFLUENCE OF AN EXISTING VERTICAL STRUCTURE ON THE INCEPTION OF WAVE BREAKING POINT

2014 ◽  
Vol 1 (34) ◽  
pp. 54
Author(s):  
Dogan Kisacik ◽  
Peter Troch
Keyword(s):  
Wave Breaking ◽  
Vertical Structure ◽  
Breaking Point

scholarly journals PHYSICAL REQUIREMENTS FOR A TAKEOFF IN SURFING

2017 ◽  
pp. 30
Author(s):  
Akihiko Kimura ◽  
Taro Kakinuma
Keyword(s):  
Wave Front ◽  
Time Variation ◽  
Wave Breaking ◽  
Horizontal Component ◽  
Breaking Point ◽  
Front Face ◽  
The Waves

The conditions required for a takeoff in surfing, are discussed, with the waves simulated numerically, considering two types of wave breaking, i.e., a plunging type, and a spilling type. First, a surfer is required to obtain a sufficient value for the horizontal component of paddling speed, not to be overtaken by a wave peak. Second, when the surfer stops paddling, he needs to be floating at a location where the force on him is downward, along the wave front face. On the basis of both conditions, the time variation of the required value for the horizontal component of paddling speed, is evaluated for both the plunging-type, and spilling-type, cases. When the paddling speed is sufficient, the surfable area is larger in the former case, than in the latter, on the offshore side of the wave-breaking point.

Prediction of Water Wave Breaking Height and Depth Using ANFIS

2011 ◽  
Author(s):  
Ehsan Delavari ◽  
Ahmad Reza Mostafa Gharabaghi ◽  
Mohammad Reza Chenaghlou
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Fuzzy Inference System ◽  
Wave Breaking ◽  
Fuzzy Inference ◽  
Breaking Point ◽  
Empirical Equations ◽  
Anfis Model ◽  
Inference System ◽  
Semi Empirical

Wave height as well as water depth at the breaking point are two basic parameters which are necessary for studying coastal processes. In this paper, the application of Fuzzy Inference System (FIS) and Adaptive Neuro-Fuzzy Inference System (ANFIS) and semi-empirical models are investigated. The data sets used in this study are published laboratory data obtained from regular wave breaking on plane, impermeable slopes collected from 22 sources. Results indicate that the developed ANFIS model provides more accurate and reliable estimation of breaking wave height, compared to semi-empirical equations. However, some of semi-empirical equations provide better predictions of water depth at the breaking point compared to the ANFIS model.

scholarly journals On the Vertical Structure of Wind-Driven Sea Currents

2008 ◽  
Vol 38 (10) ◽  
pp. 2121-2144 ◽  
Author(s):  
Vladimir Kudryavtsev ◽  
Victor Shrira ◽  
Vladimir Dulov ◽  
Vladimir Malinovsky
Keyword(s):  
Boundary Layer ◽  
Wave Breaking ◽  
Vertical Structure ◽  
Sea Surface ◽  
Experimental Fact ◽  
Semiempirical Model ◽  
Surface Currents ◽  
Cool Temperature ◽  
Wall Boundary Layer ◽  
Wall Boundary

Abstract The vertical structure of wind-driven sea surface currents and the role of wind-wave breaking in its formation are investigated by means of both field experiments and modeling. Analysis of drifter measurements of surface currents in the uppermost 5-m layer at wind speeds from 3 to 15 m s−1 is the experimental starting point of this study. The velocity gradients beneath the surface are found to be 2 to 5 times weaker than in the “wall” boundary layer. Surface wind drift (identified via drift of an artificial slick) with respect to 0.5-m depths is about 0.7%, which is even less than the velocity defect over the molecular sublayer in the wall boundary layer at a smooth surface. To interpret the data, a semiempirical model describing the effect of wave breaking on wind-driven surface currents and subsurface turbulence is proposed. The model elaborates on the idea of direct injection of momentum and energy from wave breaking (including microscale breaking) into the water body. Momentum and energy transported by breaking waves into the water significantly enhance the turbulent mixing and considerably decrease velocity shears as compared to the wall boundary layer. No “artificial” surface roughness scale is needed in the model. From the experimental fact of the existence of cool temperature skin at the sea surface, it is deduced that there is a molecular sublayer at the water side of the sea surface with a thickness that depends on turbulence intensity just beneath the surface. The model predictions are consistent with the reported and other available experimental data.

Vertical Structure of Dissipation in the Nearshore

2007 ◽  
Vol 37 (7) ◽  
pp. 1764-1777 ◽  
Author(s):  
Falk Feddersen ◽  
J. H. Trowbridge ◽  
A. J. Williams
Keyword(s):  
Boundary Layer ◽  
Wave Breaking ◽  
Vertical Structure ◽  
Vertical Shear ◽  
Bottom Boundary Layer ◽  
Breaking Wave ◽  
Vertical Diffusion ◽  
Turbulent Length Scale ◽  
Bottom Boundary ◽  
Shear Production

Abstract The vertical structure of the dissipation of turbulence kinetic energy was observed in the nearshore region (3.2-m mean water depth) with a tripod of three acoustic Doppler current meters off a sandy ocean beach. Surface and bottom boundary layer dissipation scaling concepts overlap in this region. No depth-limited wave breaking occurred at the tripod, but wind-induced whitecapping wave breaking did occur. Dissipation is maximum near the surface and minimum at middepth, with a secondary maximum near the bed. The observed dissipation does not follow a surfzone scaling, nor does it follow a “log layer” surface or bottom boundary layer scaling. At the upper two current meters, dissipation follows a modified deep-water breaking-wave scaling. Vertical shear in the mean currents is negligible and shear production magnitude is much less than dissipation, implying that the vertical diffusion of turbulence is important. The increased near-bed secondary dissipation maximum results from a decrease in the turbulent length scale.

scholarly journals Numerical Simulations of Non-Breaking, Breaking and Broken Wave Interaction with Emerged Vegetation Using Navier-Stokes Equations

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2561 ◽  
Author(s):  
Xuefeng Zou ◽  
Liangsheng Zhu ◽  
Jun Zhao
Keyword(s):  
Wave Propagation ◽  
Wave Height ◽  
Wave Breaking ◽  
Surf Zone ◽  
Stokes Equations ◽  
Wave Interaction ◽  
Breaking Waves ◽  
Breaking Point ◽  
Navier Stokes ◽  
Inertia Force

Coastal plants can significantly dissipate water wave energy and services as a part of shoreline protection. Using plants as a natural buffer from wave impacts remains an attractive possibility. In this paper, we present a numerical investigation on the effects of the emerged vegetation on non-breaking, breaking and broken wave propagation through vegetation over flat and sloping beds using the Reynolds-average Navier-Stokes (RANS) equations coupled with a volume of fluid (VOF) surface capturing method. The multiphase two-equation k-ω SST turbulence model is adopted to simulate wave breaking and takes into account the effects enhanced by vegetation. The numerical model is validated with existing data from several laboratory experiments. The sensitivities of wave height evolution due to wave conditions and vegetation characteristics with variable bathymetry have been investigated. The results show good agreement with measured data. For non-breaking waves, the wave reflection due to the vegetation can increase wave height in front of the vegetation. For breaking waves, it is shown that the wave breaking behavior can be different when the vegetation is in the surf zone. The wave breaking point is slightly earlier and the wave height at the breaking point is smaller with the vegetation. For broken waves, the vegetation has little effect on the wave height before the breaking point. Meanwhile, the inertia force is important within denser vegetation and is intended to decrease the wave damping of the vegetation. Overall, the present model has good performance in simulating non-breaking, breaking and broken wave interaction with the emerged vegetation and can achieve a better understanding of wave propagation over the emerged vegetation.

scholarly journals Nonlinear Characteristics of Internal Waves in a Deep-Water Region or near a Wave-Breaking Point

2010 ◽  
Vol 66 (1) ◽  
pp. 26-30
Author(s):  
Kei YAMASHITA ◽  
Taro KAKINUMA ◽  
Keisuke NAKAYAMA ◽  
Masayuki OIKAWA ◽  
Hidekazu TSUJI ◽  
...  
Keyword(s):  
Internal Waves ◽  
Deep Water ◽  
Wave Breaking ◽  
Breaking Point ◽  
Nonlinear Characteristics ◽  
Water Region

Drift velocity at the wave breaking point

1982 ◽  
Vol 6 (2) ◽  
pp. 121-150 ◽  
Author(s):  
Hsiang Wang ◽  
Tsuguo Sunamura ◽  
Paul A. Hwang
Keyword(s):  
Drift Velocity ◽  
Wave Breaking ◽  
Breaking Point
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