Wave Modeling
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Recent papers in Wave Modeling
This paper presents a multi-criteria analysis of potential sites intended for the construction of a petroleum export port along the North-Western shores of the Persian Gulf, with particular attention to sediment transport considerations... more
This paper presents a multi-criteria analysis of potential sites intended for the construction of a petroleum export port along the North-Western shores of the Persian Gulf, with particular attention to sediment transport considerations being necessary due to proximity of both sites
to the Mond river, as the latter acts as a considerable source of alluvial sediments, greatly influencing the geomorphology of the Persian Gulf Northern shores. Although, various criteria
interplay in the site-selection process for such a major port, however, the potential cost impact of future maintenance dredging on overall project costs is seen to be so large as to govern the final decision. Two potential port construction sites, as chosen at different distances away from the river mouth, namely, Chah-Pahn and Kabgan locations, are studied and compared, particularly from a future maintenance dredging costs point of view in order to arrive at the best overall alternative.
to the Mond river, as the latter acts as a considerable source of alluvial sediments, greatly influencing the geomorphology of the Persian Gulf Northern shores. Although, various criteria
interplay in the site-selection process for such a major port, however, the potential cost impact of future maintenance dredging on overall project costs is seen to be so large as to govern the final decision. Two potential port construction sites, as chosen at different distances away from the river mouth, namely, Chah-Pahn and Kabgan locations, are studied and compared, particularly from a future maintenance dredging costs point of view in order to arrive at the best overall alternative.
This paper presents a novel initiative for reliable high-resolution forecasts on prevailing sea states at 50 important ports worldwide (Accu-Waves; http://accuwaves.eu/). Its goal is to support safe navigation, unhampered vessel... more
This paper presents a novel initiative for reliable high-resolution forecasts on prevailing sea states at 50 important ports worldwide (Accu-Waves; http://accuwaves.eu/). Its goal is to support safe navigation, unhampered vessel approaching to busy harbored areas, and secure ship maneuvering in ports. Accu-Waves 1 is based on integrated, high-resolution, ocean and coastal modeling that uses data from global scale, open-sea forecasts as boundary conditions. The models' setup, coupling, nesting, calibration, verification, and application are reported herein, concerning areas near and inside globally significant port basins. Thus, we present the automated operational setup of the Accu-Waves service for three-day forecasts at three-hourly intervals.
Many practical seismic applications such as reverse time migration (RTM) and full-waveform inversion (FWI) are usually computation and memory intensive. To perform crosscorrelation in RTM or build the gradient for FWI, it is mandatory to... more
Many practical seismic applications such as reverse time migration (RTM) and full-waveform inversion (FWI) are usually computation and memory intensive. To perform crosscorrelation in RTM or build the gradient for FWI, it is mandatory to access the forward and adjoint wavefields simultaneously. To do this, there are three methods: One is to read the stored forward wavefield from the disk, the second is using the final snapshot and the stored boundaries via reverse propagation, and the third is remodeling using checkpointing from stored state to another state. Among these techniques, wavefield reconstruction by reverse propagation appears to be a quite straightforward approach ; however, it suffers a stringent memory bottleneck for 3D large-scale imaging applications. The Courant-Friedrichs-Lewy (CFL) condition is a fundamental criterion to determine temporal sampling to achieve stable wavefield extrapolation. The injection of the boundary sequence in time is essentially determined by Nyquist sampling principle, rather than the time interval given by CFL, which is much smaller than the Nyquist requirement. Based on this recognition, we have developed three boundary interpolation techniques, such as the discrete Fourier transform (DFT) interpolation, Kaiser windowed sinc interpolation, and Lagrange polynomial interpolation, for wave-field reconstruction to move from CFL to the Nyquist limit. Wavefield reconstruction via DFT interpolation can be implemented by folding and unfolding steps in the forward simulation and backward reconstruction on the fly. Compared with the DFT interpolation, the wavefield reconstruction methods using Kaiser windowed sinc interpolation and Lagrange polynomial interpolation have better efficiency while remaining a competitive accuracy. These methods allow us to dramatically decimate the boundary without significant loss of information, and they nicely reconstruct the boundary elements in between the samples , making the in-core memory saving of the boundaries feasible in 3D large-scale imaging applications.
In this paper we present the evolvement of an integrated numerical model (WAVE-L) for the simulation of wave propagation and transformation in areas around and inside ports and harbors. WAVE-L is a high-resolution phase-resolving wave... more
In this paper we present the evolvement of an integrated numerical model (WAVE-L) for the simulation of wave propagation and transformation in areas around and inside ports and harbors. WAVE-L is a high-resolution phase-resolving wave model based on the hyperbolic mild-slope equations, capable of simulating the transformation of complex wave fields over varying bathymetries in harbors and coastal areas in the vicinity of ports. The modeled wave processes include shoaling, refraction, diffraction, total and partial reflection from structures, energy dissipation due to wave breaking and bottom friction in a combined way. The new version of WAVE-L incorporates wave generation simulated on any boundary (longitudinal, lateral or oblique) with corresponding expansion of peripheral sponge layers, providing potential to spatially restrict the computational field in areas adjacent to ports, thus reducing demand of computational time and resources. Moreover, the modified WAVE-L version is able to simulate quasi-irregular, multi-directional waves, whose generation and propagation may furthermore account for various angles and directions simultaneously. WAVE-L is one-way coupled to coarser implementations of an open-sea spectral wave model and a 2-DH hydrodynamic circulation model for storm surges that provide input and boundary conditions. WAVE-L model is thoroughly validated against experimental data on diffraction and multidirectional spectral wave propagation; pilot implementations of it are carried out at the Greek port basin of Thessaloniki. The ultimate goal is to create a tool for high-resolution operational forecasts of wave conditions around and inside significant ports with high traffic load and commercial value (project Accu-Waves).
Forecast of wave agitation inside port basins and consequent downtime of berth positions are of utmost importance to make a port "smarter" by efficiently managing its infrastructure. Within Accu-Waves project (http://accuwaves.eu), a... more
Forecast of wave agitation inside port basins and consequent downtime of berth positions are of utmost importance to make a port "smarter" by efficiently managing its infrastructure. Within Accu-Waves project (http://accuwaves.eu), a decision-making tool is being developed to provide forecast data on prevailing sea states in the vicinity of port entrances and inside harbour basins. The said tool will be based on cooperating hydrodynamic models that derive data from global scale, open sea forecasts. The implementation of the project includes development and application of a hydrodynamic circulation model, a spectral wave propagation model and a phase-resolving wave model for port basins. The latter is based on the hyperbolic mild-slope (HMS) equations, capable of simulating wave propagation and reflection. In order to achieve higher levels of simulation accuracy in the vicinity of waterfront structures, we need to robustly model the reflection of incipient waves from such structures (e.g., quay walls). In the present paper, this need is met through the incorporation of an additional, casespecific eddy viscosity coefficient to the governing mildslope equations (of the phase-resolving wave model). This coefficient accounts for the energy dissipation on port structures' fronts and its value is decided based on the corresponding reflection coefficient. A basic set of incident wave scenarios are simulated, required in investigating the numerics of reflection by the corresponding eddy viscosity coefficients in the wave model. Our pilot investigation refers to numerical experiments for several cases of waves approaching an either fully or partially reflective vertical quay wall. The proposed methodology could enhance similar HMS models; its results should be valuable for port operators.
With the launch of Oceansat-I (IRS-P4), it became a reality to carry out validations of third generation wave model 3g-WAM in the North Indian Ocean region using the IRS-P4 analyzed wind fields provided by the National Centre for Medium... more
With the launch of Oceansat-I (IRS-P4), it became a reality to carry out validations of third generation wave model 3g-WAM in the North Indian Ocean region using the IRS-P4 analyzed wind fields provided by the National Centre for Medium Range Weather Forecasting (NCMRWF), New Delhi, India.
However, the model predicted wave fields were to be still analyzed and further validated using all available field measurements which was the primary task before the scientific community. This study, describes the wave model
validation studies carried out at Naval Physical and Oceanographic Laboratory (NPOL), Cochin, India through a collaborative research programme between NPOL and Space Application Centre (SAC), as part of the IRS-P4, MSMR Utilization Programme. Under this collaborative programme, 3g-WAM wave hindcasts were carried out for the Indian Ocean from 30E to 120E and 30S to 30N using the analyzed winds of NCMRWF and appropriate open sea
boundary inputs. WAM was executed using six hourly input fields over 1.5x1.5 grid resolution. The outputs of the model such as wave height, peak wave period, mean wave period and mean wave directions were compared with
the time-series buoy measurements of National Institute of Ocean Technology (NIOT), Chennai, India and other available measurements. Comparisons between the predicted and observed wave parameters were very encouraging.
However, the model predictions of significant wave height were overestimated during the extreme wind and wave conditions. By and large, the WAM predictions were quite reliable for the south-west monsoon (May-September)
periods in spite of the limitations. These validation studies have revealed that, the performance of WAM was satisfactory and it revealed that the hindcast wave fields of WAM for the North Indian Ocean can be utilized for various user applications in the deep waters over 30 meters.
However, the model predicted wave fields were to be still analyzed and further validated using all available field measurements which was the primary task before the scientific community. This study, describes the wave model
validation studies carried out at Naval Physical and Oceanographic Laboratory (NPOL), Cochin, India through a collaborative research programme between NPOL and Space Application Centre (SAC), as part of the IRS-P4, MSMR Utilization Programme. Under this collaborative programme, 3g-WAM wave hindcasts were carried out for the Indian Ocean from 30E to 120E and 30S to 30N using the analyzed winds of NCMRWF and appropriate open sea
boundary inputs. WAM was executed using six hourly input fields over 1.5x1.5 grid resolution. The outputs of the model such as wave height, peak wave period, mean wave period and mean wave directions were compared with
the time-series buoy measurements of National Institute of Ocean Technology (NIOT), Chennai, India and other available measurements. Comparisons between the predicted and observed wave parameters were very encouraging.
However, the model predictions of significant wave height were overestimated during the extreme wind and wave conditions. By and large, the WAM predictions were quite reliable for the south-west monsoon (May-September)
periods in spite of the limitations. These validation studies have revealed that, the performance of WAM was satisfactory and it revealed that the hindcast wave fields of WAM for the North Indian Ocean can be utilized for various user applications in the deep waters over 30 meters.
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