scholarly journals Comments to "Identification of early warning criteria for rough sea ship navigation using high-resolution numerical wave simulation and shipboard measurements" by C. Chen, K. Sasa and T. Mizojiri

2020 ◽  
Author(s):  
Anonymous
Keyword(s):  
High Resolution ◽  
Early Warning ◽  
Wave Simulation ◽  
Numerical Wave ◽  
Ship Navigation ◽  
Warning Criteria ◽  
Rough Sea

scholarly journals Identification of early warning criteria for rough sea ship navigation using high-resolution numerical wave simulation and shipboard measurements

2020 ◽  
Author(s):  
Chen Chen ◽  
Kenji Sasa ◽  
Takaaki Mizojiri
Keyword(s):  
High Risk ◽  
High Resolution ◽  
Early Warning ◽  
Surface Wind ◽  
Ocean Surface ◽  
Ocean Waves ◽  
Observation Data ◽  
Ship Navigation ◽  
Warning Criteria ◽  
Rough Sea

Abstract. The analysis of ocean surface waves are essential to ensure a safe and economical navigation. Since 2010, different onboard observation data from a bulk carrier have been colledted for 6 years, including high-risk shipping regions in the Southern Hemisphere with strong ocean currents. For four rough sea cases, high-resolution numerical simulations of ocean waves, including the effect of wave-current interaction on ship navigation, have been performed using the WAVEWATCH III model. The simulations considered the ocean surface wind force from the widely used grid point value database NCEP-FNL and ERA-Interim. Aimed at providing practical suggestions for safe navigation by avoiding possible high-risk ocean regions as well as the construction of a more effective and efficient optimum ship routing system, the model results were validated based on onboard observations, followed by discussions on the responses of ship motion and navigation to wave states at different levels. Finally, identification of the early warning criteria, including various operational ocean parameters, is provided for ballast and loaded ships sailing in rough seas.

Hydrodynamic Coupling of Viscous and Non-Viscous Numerical Wave Solutions Within the Open-Source Hydrodynamics Framework REEF3D

2021 ◽  
Author(s):  
Weizhi Wang ◽  
Csaba Pákozdi ◽  
Arun Kamath ◽  
Tobias Martin ◽  
Hans Bihs
Keyword(s):  
High Resolution ◽  
Boundary Conditions ◽  
Open Source ◽  
Laplace Equation ◽  
Scale Model ◽  
Surface Boundary ◽  
Cfd Model ◽  
Hydrodynamic Coupling ◽  
Coupling Strategy ◽  
Numerical Wave

Abstract A comprehensive understanding of the marine environment in the offshore area requires phase-resolved wave information. For the far-field wave propagation, computational efficiency is crucial, as large spatial and temporal scales are involved. For the near-field extreme wave events and wave impacts, high resolution is required to resolve the flow details and turbulence. The combined use of a computationally efficient large-scale model and a high-resolution local-scale solver provides a solution the combines accuracy and efficiency. This article introduces a coupling strategy between the efficient fully nonlinear potential flow (FNPF) solver REEF3D::FNPF and the high-fidelity computational fluid dynamics (CFD) model REEF3D::CFD within in the open-source hydrodynamics framework REEF3D. REEF3D::FNPF solves the Laplace equation together with the boundary conditions on a sigma-coordinate. The free surface boundary conditions are discretised using high-order finite difference methods. The Laplace equation for the velocity potential is solved with a conjugated gradient solver preconditioned with geometric multi-grid provided by the open-source library hypre. The model is fully parallelised following the domain decomposition strategy and the MPI protocol. The waves calculated with the FNPF solver are used as wave generation boundary condition for the CFD based numerical wave tank REEF3D::CFD. The CFD model employs an interface capturing two-phase flow approach that can resolve complex wave structure interaction, including breaking wave kinematics and turbulent effects. The presented hydrodynamic coupling strategy is tested for various wave conditions and the accuracy is fully assessed.

scholarly journals National Partnership for Maternal Safety Recommended Maternal Early Warning Criteria Are Associated With Maternal Morbidity

2019 ◽  
Vol 129 (6) ◽  
pp. 1621-1626 ◽  
Author(s):  
David E. Arnolds ◽  
Aaron Smith ◽  
Jennifer M. Banayan ◽  
Roxane Holt ◽  
Barbara M. Scavone
Keyword(s):  
Early Warning ◽  
Maternal Morbidity ◽  
Warning Criteria ◽  
National Partnership

Wave simulation in a numerical wave tank, using BEM

2015 ◽  
Author(s):  
Rezvan Alamian ◽  
Rouzbeh Shafaghat ◽  
Mohammad Javad Ketabdari
Keyword(s):  
Numerical Wave Tank ◽  
Wave Tank ◽  
Wave Simulation ◽  
Numerical Wave

Evaluation of the numerical wave model (SWAN) for wave simulation in the Black Sea

2012 ◽  
Vol 50-51 ◽  
pp. 80-99 ◽  
Author(s):  
Adem Akpınar ◽  
Gerbrant Ph. van Vledder ◽  
Murat İhsan Kömürcü ◽  
Mehmet Özger
Keyword(s):  
Black Sea ◽  
Wave Model ◽  
The Black Sea ◽  
Wave Simulation ◽  
Numerical Wave
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