Directional Analysis and Potential for Spectral Modelling of Infragravity Waves

2016 ◽  
Author(s):  
Takehiko Nose ◽  
Alexander Babanin ◽  
Kevin Ewans
Keyword(s):  
Wind Wave ◽  
Wind Waves ◽  
Field Research ◽  
Army Corps ◽  
Relative Depth ◽  
Infragravity Waves ◽  
Directional Information ◽  
Us Army ◽  
Dynamic Relationship ◽  
Infragravity Wave

In this paper, we interrogated wave data collected by US Army Corps of Engineers at their well-known Field Research Facility, Duck, North Carolina and SHELL Corporation at Lagos, Nigeria. Both measurements were designed to collect wind waves with a conventional wave sampling configuration and not a dedicated infragravity wave sampling regime. Here, we developed a new approach to obtain directional information of and explored the potential to model infragravity waves in the spectral domain. It was found that infragravity wave heights had a strong dynamic relationship with an inverse relative depth parameter and that directional spreadings were moderately correlated with wind wave spreadings and wave energy. Further, infragravity directional spreadings were typically broader compared to their wind wave directional spreading counterparts.

scholarly journals FRF WAVE TEST BED AND BATHYMETRY INVERSION

2017 ◽  
pp. 22 ◽  
Author(s):  
Jane McKee Smith ◽  
Spicer Bak ◽  
Tyler Hesser ◽  
Mary A. Bryant ◽  
Chris Massey
Keyword(s):  
Numerical Models ◽  
Field Research ◽  
Wave Model ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Test Bed ◽  
Inversion Algorithm ◽  
Us Army ◽  
Spectral Wave Model ◽  
Limited Application

An automated Coastal Model Test Bed has been built for the US Army Corps of Engineers Field Research Facility to evaluate coastal numerical models. In October of 2015, the test bed was expanded during a multi-investigator experiment, called BathyDuck, to evaluate two bathymetry sources: traditional survey data and bathymetry generated through the cBathy inversion algorithm using Argus video measurements. Comparisons were made between simulations using the spectral wave model STWAVE with half-hourly cBathy bathymetry and the more temporally sparse surveyed bathymetry. The simulation results using cBathy bathymetry were relatively close to those using the surveyed bathymetry. The largest differences were at the shallowest gauges within 250 m of the coast, where wave model normalized root-mean-square was approximately twice are large using the cBathy bathymetry. The nearshore errors using the cBathy input were greatest during events with wave height greater than 2 m. For this limited application, the Argus cBathy algorithm proved to be a suitable bathymetry input for nearshore wave modeling. cBathy bathymetry was easily incorporated into the modeling test bed and had the advantage of being updated on approximately the same temporal scale as the other model input conditions. cBathy has great potential for modeling applications where traditional surveys are sparse (seasonal or yearly).

Characteristics of the Infragravity Wave Climate

2008 ◽  
Author(s):  
Stephen Masterton ◽  
Kevin Ewans
Keyword(s):  
Oil And Gas ◽  
Wind Waves ◽  
Wave Climate ◽  
Peak Period ◽  
Infragravity Waves ◽  
Design Practices ◽  
The Us ◽  
Near Shore ◽  
Wave Models ◽  
Infragravity Wave

Infragravity waves are very long period waves below the frequency of typical wind waves. They are most significant in shallow water locations and therefore have a high impact on the response of moored vessels. For the Oil and Gas business this can be an important consideration for tanker on/offloading operations (including LNG vessels) — these larger vessels, with longer natural periods, are particularly susceptible. There are implications for both the design and operation including the calculation of extreme loading on the mooring system, extreme vessel motions, fatigue of mooring systems and the availability of on/offloading operations. There are currently limited design practices to account for the effect of infragravity waves. This may be attributed to two main factors: The development of infragravity waves is difficult to model and is sensitive to many factors, including the magnitude and shape of the incident wind and swell spectra, local bathymetry, directionality and near shore wave breaking. Secondly, very little measured data exist since the infragravity wave frequencies lie below the conventional range of commonly deployed wave measurement devices. The present paper will provide a description of the infragravity waves acting on the US coast at two locations, Duck, North Carolina, and Baja, California. The results will characterize parameters including the significant wave height, peak period, and comparison of infragravity waves through time. In addition, the relationships between the spectral shape will be examined including directionality. This type of information is needed to set design criteria for infragravity waves, and in the longer term to develop and enhance infragravity wave models e.g. Reniers 2002 (1) and ultimately contribute to establishing design practices.

scholarly journals ADVANCES IN THE UNSTRUCTURED WAVEWATCH III AND APPLICATION TO HURRICANE DORIAN

2020 ◽  
pp. 42
Author(s):  
Jane McKee Smith ◽  
Tyler Hesser ◽  
Mary Anderson Bryant ◽  
Aron Roland ◽  
Andrew Cox
Keyword(s):  
Rapid Development ◽  
Field Research ◽  
Propagation Model ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Wavewatch Iii ◽  
Us Army ◽  
Spatial Coverage ◽  
The Us ◽  
Hurricane Storm Surge

The spectral wave generation and propagation model WAVEWATCH III (WW3) is undergoing rapid development to extend capability and applicability. An option for unstructured grids and implicit solution provides WW3 with the flexibility and efficiency to resolve complex shorelines and high-gradient wave zones to drive nearshore circulation, wave setup, and wave-driven sediment transport with multi-scale spatial coverage over approximately three orders of magnitude. The model is compatible with community-based coupling infrastructure to facilitate two-way coupling with circulation models for simulating hurricane storm surge and waves. Unstructured WW3 is applied for 2019 Hurricane Dorian and validated with National Data Buoy Center buoys and nearshore gauges at the US Army Corps of Engineers Field Research Facility.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/kz9G46xUD0k

scholarly journals PLANNING, PRELIMINARY DESIGN, AND INITIAL PERFORMANCE OF THE NAGS HEAD BEACH NOURISHMENT PROJECT

2012 ◽  
Vol 1 (33) ◽  
pp. 109 ◽  
Author(s):  
Timothy W Kana ◽  
Haiqing Liu Kaczkowski
Keyword(s):  
Field Research ◽  
Beach Nourishment ◽  
The United States ◽  
High Energy ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Us Army ◽  
Erosion Rates ◽  
Large Gradient ◽  
Million Cubic Meter

A 3.5 million cubic meter beach nourishment project was completed along 16 kilometers of shoreline at Nags Head, North Carolina, 32 kilometers south of the US Army Corps of Engineers Field Research Facility at Duck. The project is the largest locally-funded nourishment accomplished to date in the United States. Three ocean-certified hopper dredges and one cutterhead suction dredge constructed the project between May and October 2011. This paper discusses the planning, design, and initial performance of the project. Nags Head is exposed to high waves from the northeast which generate net southerly transport over the long term. A key design issue for the project was the large gradient in erosion rates from north to south. Fill sections were varied accordingly based on documented volume erosion rates and model simulations for the area. Permitting involved over five years of environ¬mental reviews because of the need to work during fair-weather summer months in the relatively high-energy setting. The design also built on prior work in connection with a federal nourishment project scheduled for the area if and when funds become available. Two offshore areas strategically located close to south Nags Head were utilized for construction which proceeded efficiently under summer waves until late August when Hurricane Irene impacted the area. The hurricane and fall northeast storms produced rapid adjustment of the construction profile but no net loss of sand from the project area. Post-project surveys show initial profile equilibration was largely confined to the inshore zone inside the 3.7 meter (m) [−12 foot (ft) NAVD] contour. Depth of closure at decadal scales is estimated to be −7.3 m (−24 ft NAVD).

scholarly journals Loop-Type Wave-Generation Method for Generating Wind Waves under Long-Fetch Conditions

2017 ◽  
Vol 34 (10) ◽  
pp. 2129-2139 ◽  
Author(s):  
Naohisa Takagaki ◽  
Satoru Komori ◽  
Mizuki Ishida ◽  
Koji Iwano ◽  
Ryoichi Kurose ◽  
...  
Keyword(s):  
Wind Wave ◽  
Wind Waves ◽  
Peak Frequency ◽  
Wave Generation ◽  
New Wave ◽  
Wave Tank ◽  
Irregular Wave ◽  
Wind Speeds ◽  
Type Wave ◽  
Wave Generator

AbstractIt is important to develop a wave-generation method for extending the fetch in laboratory experiments, because previous laboratory studies were limited to the fetch shorter than several dozen meters. A new wave-generation method is proposed for generating wind waves under long-fetch conditions in a wind-wave tank, using a programmable irregular-wave generator. This new method is named a loop-type wave-generation method (LTWGM), because the waves with wave characteristics close to the wind waves measured at the end of the tank are reproduced at the entrance of the tank by the programmable irregular-wave generator and the mechanical wave generation is repeated at the entrance in order to increase the fetch. Water-level fluctuation is measured at both normal and extremely high wind speeds using resistance-type wave gauges. The results show that, at both wind speeds, LTWGM can produce wind waves with long fetches exceeding the length of the wind-wave tank. It is observed that the spectrum of wind waves with a long fetch reproduced by a wave generator is consistent with that of pure wind-driven waves without a wave generator. The fetch laws between the significant wave height and the peak frequency are also confirmed for the wind waves under long-fetch conditions. This implies that the ideal wind waves under long-fetch conditions can be reproduced using LTWGM with the programmable irregular-wave generator.

scholarly journals PROPAGATION OF WIND WAVES ON TIDES

1988 ◽  
Vol 1 (21) ◽  
pp. 36 ◽  
Author(s):  
Hendrick L. Tolman
Keyword(s):  
Wave Propagation ◽  
Wind Wave ◽  
Numerical Models ◽  
Wind Waves ◽  
Absolute Frequency ◽  
Shelf Seas ◽  
Shelf Sea

Effects of instationary depths and currents in tides on shelf seas on wind wave propagation are investigated using two numerical models in two academical situations representing shelf sea conditions. It is shown that changes in absolute frequency, which are induced by the instationarity of depth and current, are significant in contrast to what is usually assumed. If these changes are neglected large and unpredictable errors may occur in calculated changes of wavenumber and amplitude.

scholarly journals The Influence of Land Use Change and Spatial Discretization of Middle - Lower Ciliwung Sub-Watershed on Flood Hydrograph at Manggarai Weir : a Preliminary Study

2018 ◽  
Vol 7 (3.30) ◽  
pp. 497
Author(s):  
Nonik Eko Wahyuning Tiyas ◽  
Dwita Sutjiningsih
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Army Corps ◽  
Spatial Discretization ◽  
Rapid Urbanization ◽  
Us Army ◽  
Impervious Area ◽  
Strategic Value ◽  
Flood Hydrograph ◽  
Lowland Area

Jakarta is a lowland area with 40% of its territory at an elevation below the sea level so it is very vulnerable to flooding. One of out many causes floods in Jakarta is by the overflow of the Ciliwung River. The Ciliwung Watershed has a very strategic value in Indonesia because the Ciliwung River is one of thirteen rivers crossing the nation's capital. The rapid urbanization and population growth led to an increasing impervious area in the Ciliwung Watershed which resulted in a flood hydrograph change. This research aims to determine the influence of land use change, which is taking into account the spatial discretization and the riparian characteristic of Middle - Lower Ciliwung Sub-Watershed on flood hydrograph at Manggarai Weir. This research reviews the related literature on the implementation of HEC-GeoHMS version 10.1 developed by US Army Corps of Engineers (2013) to estimate the effect of land use change on flood hydrographs by taking into account the characteristics of the riparian described descriptively and present arguments to claim that the discretization spatial method can provide significantly more flood hydrographs results with existing conditions.  

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