On the Problem of Modeling the Boat Wake Climate: The Florida Intracoastal Waterway

Forlini, Carola; Qayyum, Rizwan; Malej, Matt; Lam, Michael; Shi, Fengyan; Angelini, Christine; Sheremet, A.

doi:10.1029/2020jc016676

Cited by 16 publications

(10 citation statements)

References 44 publications

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“…According to the method of stationary phase, these end-point contributions are formally smaller than those associated with the stationary points (where partial derivatives of g 1,2 vanish), however in certain instances (for example, when the dimensionless measure of acceleration is large) they help explain unexpected features in the timefrequency domain. For these end-point contributions, we say they occur at t = τ e , so that at the start and final times, we have τ = τ e = 0 and τ = τ e = t f , respectively; in both cases, the relevant k is given implicitly through (12) and the frequency is then computed via by the dispersion function (2). These contributions therefore correspond to frequencies ω as a function of time that can be plotted on top of the spectrograms.…”

Section: B Methods Of Stationary Phasementioning

confidence: 99%

“…where the time coordinate is equivalent to (12). In order to derive the classical dispersion curve, we rewrite (13) as…”

Section: Geometric Argumentsmentioning

confidence: 99%

“…The tool we employ to achieve this goal is the spectrogram, which uses short-time Fourier transforms to decompose each wave signal from the fixed sensor into a time-frequency heat-map. In recent times, some success has been achieved in using spectrograms to identify different features of ship wakes (eg., their transverse and divergent waves) observed in real shipping channels and in experimental towing tanks [2,3,[5][6][7][8][9][10][11][12]. The theory for this line of enquiry has been almost entirely for steadily moving ships [1,3,5,8], with very brief studies of accelerating ships moving in one direction [1,5].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Spectrogram analysis of surface elevation signals due to accelerating ships

Pethiyagoda¹,

Moroney²,

Macfarlane³

et al. 2021

Preprint

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Spectrograms provide an efficient way to analyse surface elevation signals of ship waves taken from a sensor fixed at a single point in space. Recent work based on a simplified model for the ship's disturbance suggests that matching the spectrogram heat-map patterns to a so-called dispersion curve has the potential for estimating of properties of a steadily moving ship, such as the ship's speed and closest distance to the sensor. Here we extend the theory behind the dispersion curve so that it can be applied to ships accelerating along arbitrary paths and demonstrate how acceleration affects the structure of the associated spectrograms. Examples are provided for of a simple model of a ship accelerating/decelerating in a straight line or travelling in a circle with constant angular speed. We highlight a problem with non-uniqueness of the dispersion curve when comparing ships moving along different paths. Finally, we validate the new dispersion curve against experimental results of ship models accelerating in a finite depth basin. Our work will provide a basis for more comprehensive studies that extend the simplified model to take into account the shape of the hull in question.

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Section: B Methods Of Stationary Phasementioning

confidence: 99%

“…where the time coordinate is equivalent to (12). In order to derive the classical dispersion curve, we rewrite (13) as…”

Section: Geometric Argumentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectrogram analysis of surface elevation signals due to accelerating ships

Pethiyagoda¹,

Moroney²,

Macfarlane³

et al. 2021

Preprint

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show abstract

“…This model contains a ship wake module added to the existing Boussinesq formulation, modelling vessels as a moving pressure source (Shi et al, 2018). The model was validated (Shi et al, 2018) using laboratory data (Gourlay, 2001) examining supercritical wake in various flow regimes including slow-moving, large container ships (Forlini et al, 2021). The model was first used to inform installation design by simulating conditions with and without the THGs, comparing maximum velocities and water surface elevations (Williams, Forthcoming 2022).…”

Section: Funwave-tvdmentioning

confidence: 99%

Ship wake forcing and performance of a living shoreline segment on an estuarine shoreline

Everett

Williams

Ruggiero

et al. 2022

Front. Built Environ.

Self Cite

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Investigation of the effectiveness of Natural and Nature-Based Features (NNBF) for protecting shorelines from ship wake is increasingly important with continued development along the coast, especially when combined with sea level rise. Studies that investigate the wave energy dissipation capacity of different techniques and account for variation in context will lead to improvements and innovation in designed NNBF. Few studies have examined the performance of NNBF in protecting shorelines from ship wake. In this study of a low-sloping estuarine shoreline adjacent to a major shipping route, a natural design using coir logs and wooden staking was implemented in a T-head groin configuration. Pressure transducers and electromagnetic current meters were deployed over ∼1.5 months to investigate the energy dissipation and velocity attenuation capabilities of the installation. Results indicate that ship wakes account for 25%–50% of the total daily energy impacting the shoreline at the study site. Peak background velocities are typically over 50% smaller than the largest ship wake velocities. Field data and results of the fully nonlinear Boussinesq model, FUNWAVE-TVD, indicate that the installation is capable of decreasing energy impacting the shoreline by 10%–80% and is effective over the lower 50% of the tidal range and when submerged up to twice its height. Elevation surveys of the site indicate accrual of sediment within the installation, suggesting wave diffraction patterns promoting further accretion at the site over time. Observations indicate that coir logs may be effective in reducing wave energy from ship wakes but may fail under storm conditions in a moderate fetch confined channel. Findings from this study illustrate the opportunities and challenges nature-based solutions face in addressing ship wakes, and their ability to protect shorelines under high energy stressors.

show abstract

“…The tool we employ to achieve this goal is the spectrogram, which uses short-time Fourier transforms to decompose each wave signal from the fixed sensor into a time-frequency heat-map. In recent times, some success has been achieved in using spectrograms to identify different features of ship wakes (e.g., their transverse and divergent waves) observed in real shipping channels and in experimental towing tanks [2,3,[5][6][7][8][9][10][11][12][13]. The theory for this line of enquiry has been almost entirely for steadily moving ships [1,3,5,8], with very brief studies of accelerating ships moving in one direction [1,5].…”

Section: Introductionmentioning

confidence: 99%

Spectrogram analysis of surface elevation signals due to accelerating ships

et al. 2021

View full text Add to dashboard Cite

Spectrograms provide an efficient way to analyze surface elevation signals of ship waves taken from a sensor fixed at a single point in space. Recent work based on a simplified model for the ship's disturbance suggests that matching the spectrogram heat-map patterns to a so-called dispersion curve has the potential for estimating of properties of a steadily moving ship, such as the ship's speed and closest distance to the sensor. Here we extend the theory behind the dispersion curve so that it can be applied to ships accelerating along arbitrary paths and demonstrate how acceleration affects the structure of the associated spectrograms. Examples are provided for a simple model of a ship accelerating/decelerating in a straight line or traveling in a circle with constant angular speed. We highlight a problem with nonuniqueness of the dispersion curve when comparing ships moving along different paths. Finally, we validate the new dispersion curve against experimental results of ship models accelerating in a finite depth basin. Our work will provide a basis for more comprehensive studies that extend the simplified model to take into account the shape of the hull in question.

show abstract

On the Problem of Modeling the Boat Wake Climate: The Florida Intracoastal Waterway

Cited by 16 publications

References 44 publications

Spectrogram analysis of surface elevation signals due to accelerating ships

Spectrogram analysis of surface elevation signals due to accelerating ships

Ship wake forcing and performance of a living shoreline segment on an estuarine shoreline

Spectrogram analysis of surface elevation signals due to accelerating ships

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