A numerical method for the solution of the three-dimensional acoustic wave equation in a marine environment considering complex sources

Petris, Giovanni; Cianferra, Marta; Armenio, Vincenzo

doi:10.1016/j.oceaneng.2022.111459

Cited by 11 publications

(4 citation statements)

References 28 publications

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“…For the latter, an absorbing layer technique is used based on the Perfectly Matched Layer (PML) for ensuring efficient attenuation within the layer with minimum backscattering. Such methods were recently considered for the solution of the 3D acoustic wave equation in marine environment forced by complex sources, see e.g., [13]. Numerical results are presented for various interesting cases illustrating the applicability of the present method.…”

Section: Introductionmentioning

confidence: 94%

A Novel FDTD–PML Scheme for Noise Propagation Generated by Biomimetic Flapping Thrusters in the Ocean Environment

Malefaki

Belibassakis

2022

JMSE

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Biomimetic flapping-foil thrusters can operate efficiently while offering desirable levels of thrust required for the propulsion of a small vessel or an Autonomous Underwater Vehicle (AUV). These systems have been studied both as main propulsion devices and for augmenting ship propulsion in waves. In this work, the unsteady hydrofoil loads are used to calculate the source terms of the Ffowcs Williams–Hawkings (FW-H) equation which is applied to model noise propagation in the underwater ocean acoustic environment. The solution provided by a simplified version of the Farassat formulation in free space is extended to account for a bounded domain and an inhomogeneous medium, characterizing the sea acoustic waveguide. Assuming the simplicity azimuthal symmetry of the environmental parameters, a numerical model is developed based on a Finite Difference Time Domain (FDTD) scheme, incorporating free-surface and seabed effects, in the presence of a variable sound speed profile. For the treatment of the outgoing radiating field, a Perfectly Matched Layer (PML) technique is implemented. Numerical results are presented illustrating the applicability of the method.

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Section: Introductionmentioning

confidence: 94%

A Novel FDTD–PML Scheme for Noise Propagation Generated by Biomimetic Flapping Thrusters in the Ocean Environment

Malefaki

Belibassakis

2022

JMSE

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“…Numerical methods are mathematical techniques used to approximate solutions to problems that are difficult or impossible to solve analytically [33][34][35]. One such problem is wave speed and direction simulation, which can be approximated using the finite difference method and the Fourier transform.…”

Section: Numerical Modelling and Simulationmentioning

confidence: 99%

“…In numerical modeling, the continuous values are transformed into a discretized form. Discretization approximates a continuous function or system by a discrete set of points or values [33][34][35][36][37][38]. This process is often used in numerical methods such as the finite difference method and the Fourier transform.…”

Section: Numerical Modelling and Simulationmentioning

confidence: 99%

Assessing the Feasibility of Wave Energy Harvesting through Coastal Wave Modeling and Forecasting with Long Short-Term Memory Optimization using Univariate Time Series Approach

Lawal¹,

Yassin²,

Lai³

2023

Preprint

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. Accurate coastal wave direction and speed forecasts are crucial in coastal and marine engineering, marine energy, maritime transport, fisheries, naval navigation, environmental research, and risk management. Approximately 269 km of Brunei Darussalam's coastline can generate between 15 and 126 GW of wave energy. As part of the preliminary feasibility study of wave energy harvesting in Brunei Darussalam and net zero commitment, in this study, we used two numerical methods, namely, finite difference and spectral element methods, for modeling and simulation of wave speed and direction. The mean error between numerical and analytical solutions was calculated in each simulation. Explanatory data analysis was used to provide insight into the study data. We then proposed wave direction and speed forecasting models using Long Short-Term Memory (LSTM) stacking on the data computed from the Acoustic Doppler Current Profiler (ADCP) sensor data. A univariate time series forecasting approach was adopted for this research. KerasTuner hyperparameter tuning API was used for tuning and optimizing hyperparameters, leading us to build models with the least training and test errors. Seven separate prediction experiments were conducted for wave speed and direction in degree and radian units for the next 1, 3, 6, 8, 10, 12, and 24 hours, respectively. Mean squared error (MSE) was used as a metric for both training and testing. The experimental results show that wave speed forecast has the lowest MSEs compared to direction, regardless of the unit of measure, but has a longer runtime. Moreover, the forecast of direction in the degree unit has the least errors compared to the radian unit; the running time of the latter is higher than that of the former. In the future, we intend to use advanced multivariate time series techniques to forecast wave speed and direction.

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“…In numerical modeling, the continuous values are converted into a discretized form. Discretization approximates a continuous function or system by a discrete set of points or values [33,38]. This process is commonly used in numerical methods such as the finite difference method and the Fourier transform.…”

Section: Numerical Modelling and Simulationmentioning

confidence: 99%

Coastal Wave Modeling and Forecasting with LSTM Optimization For Sustainable Energy Harvesting

Lawal¹,

Yassin²,

Lai³

2023

Preprint

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Coastal wave modeling and forecasting are essential in oceanography, sustainable marine energy, and ocean engineering. Precise forecasting of wave speed and direction are crucial for offshore operations, marine energy, risk management, environmental management, coastal and sustainable maritime management. The coastline of Brunei Darussalam can generate between 15 and 126 Giga Watt of wave energy. In this experimental research, we used two numerical approaches, the finite difference, and spectral element methods, to model and simulate wave speed and direction. We calculated the mean error between numerical and analytical solutions. We proposed a novel, promising, univariate time series forecasting model by combining the Long Short-Term (LSTM) with KerasTuner hyperparameters tuning and optimization techniques. This method helps us to improve the accuracy and efficiency of time-series forecasting.. The experimental data was computed from high-precision Acoustic Doppler Current Profiler (ADCP) sensor data. This research is part of the preliminary feasibility analysis of wave energy production in Brunei Darussalam and net zero commitment for a sustainable environment. Seven independent forecast experiments were performed for wave speed and direction in degree and radian units for 1, 3, 6, 8, 10, 12, and 24 hours. Mean squared error (MSE) was adopted as a metric for both training and testing. The experimental results reveal that the wave speed forecast has the lowest MSE compared to direction, regardless of the unit of measure, but has a longer duration. In addition, the direction forecast in the degree unit has the lowest errors compared to the unit of radians; the latter has a longer running time than the former. The model has delivered optimal results throughout the experiments with minor training and test errors. We conducted a thorough evaluations on two benchmark time series datasets, which include the study dataset and air quality index dataset, to validate the performance of the proposed model with other models. The proposed model outperforms cutting-edge forecasting models, such as the conventional LSTM, ARIMA, and Prophet. The model has the slightest forecast error compared to the existing literature’s result.

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A numerical method for the solution of the three-dimensional acoustic wave equation in a marine environment considering complex sources

Cited by 11 publications

References 28 publications

A Novel FDTD–PML Scheme for Noise Propagation Generated by Biomimetic Flapping Thrusters in the Ocean Environment

A Novel FDTD–PML Scheme for Noise Propagation Generated by Biomimetic Flapping Thrusters in the Ocean Environment

Assessing the Feasibility of Wave Energy Harvesting through Coastal Wave Modeling and Forecasting with Long Short-Term Memory Optimization using Univariate Time Series Approach

Coastal Wave Modeling and Forecasting with LSTM Optimization For Sustainable Energy Harvesting

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