EFFECT OF WAVE-CURRENT INTERACTION ON WAVES AND CIRCULATION OVER GEORGES BANK DURING STORM EVENTS

2017 ◽  
pp. 18
Author(s):  
Dongmei Xie ◽  
Qingping Zou
Keyword(s):  
Wave Height ◽  
Gulf Of Maine ◽  
North Atlantic Ocean ◽  
High Tide ◽  
Circulation Model ◽  
Georges Bank ◽  
Induced Current ◽  
Storm Events ◽  
Current Interaction ◽  
Wave Induced

The coupled spectral wave and circulation model SWAN+ADCIRC was applied to investigate the wave-current interaction during storm events over Georges Bank, a large shallow submarine bank on the eastern seaboard of North America that separates Gulf of Maine from the North Atlantic Ocean. The current over the Georges Bank displays a rotary feature over a tidal cycle. The wave-induced current is in the same order as the wind-driven current and generally in the same direction as the depth-averaged tidal current, indicating strong nonlinear wave-current interaction. The magnitude of wave-induced current reaches 0.07 m/s at low tide and 0.2 m/s at the other three tidal phases. The effect of wave-current interaction on waves at the four tidal phases is also analyzed. The role of Georges Bank in dissipating wave energy is most significant at rising mid-tide and high tide, which is close to the storm peak. At rising mid-tide, the wave height is decreased by 0.3 m to 0.5 m over the majority of the bank when the wave propagates in the same direction as the current. At falling-mid tide, the wave height is increased by 0.5 m at the southern flank and decreased by 0.5 m at the northern flank of the bank.

scholarly journals Iteration Coupling Simulation of Random Waves and Wave-Induced Currents

2012 ◽  
Vol 2012 ◽  
pp. 1-13
Author(s):  
Jinhai Zheng ◽  
Tianwen Wang ◽  
Gang Wang ◽  
Chenming Zhang ◽  
Chi Zhang
Keyword(s):  
Wave Field ◽  
Circulation Model ◽  
Wave Transformation ◽  
Induced Current ◽  
Random Waves ◽  
Three Dimensional Model ◽  
Current Interaction ◽  
Induced Currents ◽  
Coupling Algorithm ◽  
Wave Induced

A two-way coupling algorithm for wave-current interaction is developed and implemented into a nearshore circulation model to investigate the effects of fully wave-current interaction on irregular wave transformation over an elliptic shoal. The wave field is simulated by a spectral wave model WABED, and the wave-induced current is solved by a quasi-three-dimensional model WINCM. The surface roller effects are represented in the formulation of surface stress, and the roller characteristics are solved by a roller evolution model. The proposed two-way coupling algorithm can describe both the generation of wave-induced current and the current-induced wave transformation, which is more physically reasonable than the one-way approaches. The model test with a laboratory experiment shows that wave-induced currents have an important influence on the wave transformation, for example, the wave energy defocusing due to the strong jet-like current along the centerline of the shoal. It is revealed that the accuracy of simulated wave field can be significantly improved by taking into account the two-way wave-current interaction.

scholarly journals Coastal flooding: impact of waves on storm surge during extremes – a case study for the German Bight

2016 ◽  
Vol 16 (11) ◽  
pp. 2373-2389 ◽  
Author(s):  
Joanna Staneva ◽  
Kathrin Wahle ◽  
Wolfgang Koch ◽  
Arno Behrens ◽  
Luciana Fenoglio-Marc ◽  
...  
Keyword(s):  
Sea Level ◽  
German Bight ◽  
Wind Waves ◽  
Three Dimensional ◽  
Coupled Model ◽  
Circulation Model ◽  
Coastal Flooding ◽  
Storm Events ◽  
Extreme Storm ◽  
Wave Induced

Abstract. This study addresses the impact of wind, waves, tidal forcing and baroclinicity on the sea level of the German Bight during extreme storm events. The role of wave-induced processes, tides and baroclinicity is quantified, and the results are compared with in situ measurements and satellite data. A coupled high-resolution modelling system is used to simulate wind waves, the water level and the three-dimensional hydrodynamics. The models used are the wave model WAM and the circulation model GETM. The two-way coupling is performed via the OASIS3-MCT coupler. The effects of wind waves on sea level variability are studied, accounting for wave-dependent stress, wave-breaking parameterization and wave-induced effects on vertical mixing. The analyses of the coupled model results reveal a closer match with observations than for the stand-alone circulation model, especially during the extreme storm Xaver in December 2013. The predicted surge of the coupled model is significantly enhanced during extreme storm events when considering wave–current interaction processes. This wave-dependent approach yields a contribution of more than 30 % in some coastal areas during extreme storm events. The contribution of a fully three-dimensional model compared with a two-dimensional barotropic model showed up to 20 % differences in the water level of the coastal areas of the German Bight during Xaver. The improved skill resulting from the new developments justifies further use of the coupled-wave and three-dimensional circulation models in coastal flooding predictions.

scholarly journals Interaction between the Tidal and Seasonal Variability of the Gulf of Maine and Scotian Shelf Region

2016 ◽  
Vol 46 (11) ◽  
pp. 3279-3298 ◽  
Author(s):  
Anna Katavouta ◽  
Keith R. Thompson ◽  
Youyu Lu ◽  
John W. Loder
Keyword(s):  
Gulf Of Maine ◽  
Circulation Model ◽  
Surface Current ◽  
Maximum Speed ◽  
Georges Bank ◽  
Scotian Shelf ◽  
Linear Superposition ◽  
Dynamical Interaction ◽  
The North ◽  
Shelf Region

AbstractAs part of a broader study of ocean downscaling, the seasonal and tidal variability of the Gulf of Maine and Scotian shelf, and their dynamical interaction, are investigated using a high-resolution (1/36°) circulation model. The model’s seasonal hydrography and circulation, and its tidal elevations and currents, are compared with an observed seasonal climatology, local observations, and results from previous studies. Numerical experiments with and without density stratification demonstrate the influence of stratification on the tides. The model is then used to interpret the physical mechanisms responsible for the largest seasonal variations in the M2 surface current that occur over, and to the north of, Georges Bank. The model generates a striation pattern of alternating highs and lows, aligned with Georges Bank, in the M2 surface summer maximum speed in the Gulf of Maine. The striations are consistent with observations by a high-frequency coastal radar system and can be explained in terms of a linear superposition of the barotropic tide and the first-mode baroclinic tide, generated on the north side of Georges Bank, as it propagates into the Gulf of Maine. The seasonal changes in tidal currents in the well-mixed area on Georges Bank are due to a combination of increased sea level gradients, and lower vertical viscosity, in summer.

Modelling Study of the Influence of Wave Farm to Nearshore Wave Climate and Current

2014 ◽  
Vol 955-959 ◽  
pp. 1126-1131
Author(s):  
Fei Fan ◽  
Wei You ◽  
Zhi Xia Zhu ◽  
Pei Hua Dong
Keyword(s):  
Wave Height ◽  
Current Velocity ◽  
Absorption Rate ◽  
Wave Climate ◽  
Induced Current ◽  
Result Show ◽  
Wave Farm ◽  
Wave Induced ◽  
Modelling Study

This paper studied the changes of wave height and wave driven current in Zhangjiabu sea, which was caused by the installation of wave farm, with Delft3D model. First, the changes of wave height in Zhangjiabu were computed in condition of different absorption rate. Then, the wave induced current near Jinghaijiao cape was calculated, where the change of wave height is largest. Last, 12 points in depth of 3m are used to study the changes of wave induced current velocity. The result show that the wave height and wave driven current will decrease after the wave farm installed.

scholarly journals Environmental controls on surf zone injuries on high-energy beaches

2019 ◽  
Vol 19 (10) ◽  
pp. 2183-2205 ◽  
Author(s):  
Bruno Castelle ◽  
Tim Scott ◽  
Rob Brander ◽  
Jak McCarroll ◽  
Arthur Robinet ◽  
...  
Keyword(s):  
Wave Height ◽  
Surf Zone ◽  
High Tide ◽  
High Energy ◽  
Water Levels ◽  
Small Scale ◽  
Beach Morphology ◽  
Environmental Controls ◽  
Flow Activity ◽  
Incident Waves

Abstract. The two primary causes of surf zone injuries (SZIs) worldwide, including fatal drowning and severe spinal injuries, are rip currents (rips) and shore-break waves. SZIs also result from surfing and bodyboarding activity. In this paper we address the primary environmental controls on SZIs along the high-energy meso–macro-tidal surf beach coast of southwestern France. A total of 2523 SZIs recorded by lifeguards over 186 sample days during the summers of 2007, 2009 and 2015 were combined with measured and/or hindcast weather, wave, tide, and beach morphology data. All SZIs occurred disproportionately on warm sunny days with low wind, likely because of increased beachgoer numbers and hazard exposure. Relationships were strongest for shore-break- and rip-related SZIs and weakest for surfing-related SZIs, the latter being also unaffected by tidal stage or range. Therefore, the analysis focused on bathers. More shore-break-related SZIs occur during shore-normal incident waves with average to below-average wave height (significant wave height, Hs = 0.75–1.5 m) and around higher water levels and large tide ranges when waves break on the steepest section of the beach. In contrast, more rip-related drownings occur near neap low tide, coinciding with maximised channel rip flow activity, under shore-normal incident waves with Hs >1.25 m and mean wave periods longer than 5 s. Additional drowning incidents occurred at spring high tide, presumably due to small-scale swash rips. The composite wave and tide parameters proposed by Scott et al. (2014) are key controlling factors determining SZI occurrence, although the risk ranges are not necessarily transferable to all sites. Summer beach and surf zone morphology is interannually highly variable, which is critical to SZI patterns. The upper beach slope can vary from 0.06 to 0.18 between summers, resulting in low and high shore-break-related SZIs, respectively. Summers with coast-wide highly (weakly) developed rip channels also result in widespread (scarce) rip-related drowning incidents. With life risk defined in terms of the number of people exposed to life threatening hazards at a beach, the ability of morphodynamic models to simulate primary beach morphology characteristics a few weeks or months in advance is therefore of paramount importance for predicting the primary surf zone life risks along this coast.

scholarly journals Wave Height Distributions and Rogue Waves in the Eastern Mediterranean

2021 ◽  
Vol 9 (6) ◽  
pp. 660
Author(s):  
Sagi Knobler ◽  
Daniel Bar ◽  
Rotem Cohen ◽  
Dan Liberzon
Keyword(s):  
Wave Height ◽  
Eastern Mediterranean ◽  
Rogue Waves ◽  
Distribution Model ◽  
Storm Events ◽  
Order Model ◽  
Deep Seawater ◽  
Wave Heights ◽  
Storm Characteristics ◽  
Buoy Data

There is a lack of scientific knowledge about the physical sea characteristics of the eastern part of the Mediterranean Sea. The current work offers a comprehensive view of wave fields in southern Israel waters covering a period between January 2017 and June 2018. The analyzed data were collected by a meteorological buoy providing wind and waves parameters. As expected for this area, the strongest storm events occurred throughout October–April. In this paper, we analyze the buoy data following two main objectives—identifying the most appropriate statistical distribution model and examining wave data in search of rogue wave presence. The objectives were accomplished by comparing a number of models suitable for deep seawater waves. The Tayfun—Fedele 3rd order model showed the best agreement with the tail of the empirical wave heights distribution. Examination of different statistical thresholds for the identification of rogue waves resulted in the detection of 99 unique waves, all of relatively low height, except for one wave that reached 12.2 m in height which was detected during a powerful January 2018 storm. Characteristics of the detected rogue waves were examined, revealing the majority of them presenting crest to trough symmetry. This finding calls for a reevaluation of the crest amplitude being equal to or above 1.25 the significant wave height threshold which assumes rogue waves carry most of their energy in the crest.

THE INFLUENCE OF CENTRE BOW LENGTH ON SLAMMING LOADS AND MOTIONS OF LARGE WAVE-PIERCING CATAMARANS

2021 ◽  
Vol 160 (A1) ◽  
Author(s):  
J R Shahraki ◽  
G A Thomas ◽  
M R Davis
Keyword(s):  
Wave Height ◽  
Full Scale ◽  
Bending Moments ◽  
Regular Waves ◽  
Large Wave ◽  
Towing Tank ◽  
Segmented Model ◽  
Model Experiments ◽  
Slamming Load ◽  
Wave Induced

The effect of various centre bow lengths on the motions and wave-induced slamming loads on wave-piercing catamarans is investigated. A 2.5 m hydroelastic segmented model was tested with three different centre bow lengths and towed in regular waves in a towing tank. Measurements were made of the model motions, slam loads and vertical bending moments in the model demi-hulls. The model experiments were carried out for a test condition equivalent to a wave height of 2.68 m and a speed of 20 knots at full scale. Bow accelerations and vertical bending moments due to slamming showed significant changes with the change in centre bow, the longest centre bow having the highest wave-induced loads and accelerations. The increased volume of displaced water which is constrained beneath the bow archways is identified as the reason for this increase in the slamming load. In contrast it was found that the length of centre bow has a relatively small effect on the heave and pitch motions in slamming conditions.

Effects of wave-induced forcing on a circulation model of the North Sea

2016 ◽  
Vol 67 (1) ◽  
pp. 81-101 ◽  
Author(s):  
Joanna Staneva ◽  
Victor Alari ◽  
Øyvind Breivik ◽  
Jean-Raymond Bidlot ◽  
Kristian Mogensen
Keyword(s):  
North Sea ◽  
Circulation Model ◽  
The North ◽  
The North Sea ◽  
Wave Induced
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