Browsing NTNU Open by Author "Pakozdi, Csaba"
Now showing items 1-20 of 26
-
Application of Arbitrary Lagrangian-Eulerian Strips with Fully Nonlinear Wave Kinematics for Force Estimation
Pakozdi, Csaba; Kamath, Arun; Wang, Weizhi; Bihs, Hans (Journal article; Peer reviewed, 2022)The initial design of offshore constructions generally uses a combination of model tests and second-order wave theory to reconstruct the wave kinematics to determine wave forces using the Morison equation. This routine ... -
CFD Based Study of Steep Irregular Waves for Extreme Wave Spectra
Aggarwal, Ankit; Alagan Chella, Mayilvahanan; Bihs, Hans; Pakozdi, Csaba; Berthelsen, Petter Andreas; Arntsen, Øivind Asgeir (Journal article; Peer reviewed, 2017)Offshore structures are exposed to irregular sea states. It consists of breaking and non-breaking waves. They experience extreme wave loads perpetually after being installed in the open ocean. Thus, the study of steep waves ... -
CFD modelling of irregular and focused waves using wave reconstruction
Aggarwal, Ankit; Alagan Chella, Mayilvahanan; Bihs, Hans; Pakozdi, Csaba; Arntsen, Øivind Asgeir (Chapter, 2017)The real sea state is composed of the focused and steep irregular waves which makes their study very important in the design of offshore wind turbines. Computational Fluid Dynamics (CFD) can be used as an effective tool ... -
A comparison of different wave modelling techniques in an open-source hydrodynamic framework
Wang, Weizhi; Kamath, Arun; Pakozdi, Csaba; Bihs, Hans (Peer reviewed; Journal article, 2020)Modern design for marine and coastal activities places increasing focus on numerical simulations. Several numerical wave models have been developed in the past few decades with various techniques and assumptions. Those ... -
Complex geometry handling for a cartesian grid based solver
Bihs, Hans; Kamath, Arun; Alagan Chella, Mayilvahanan; Pakozdi, Csaba (Chapter, 2017)Complex geometries can be a challenge for computational fluid dynamics (CFD) solvers that use a Cartesian mesh. In the current paper, an algorithm is described with which complex geometry features can be incorporated in a ... -
Computational Fluid Dynamics Reproduction of Nonlinear Loads on a Vertical Column during Extreme Irregular Wave Events
Bachynski, Erin Elizabeth; Pakozdi, Csaba; Östman, Anders Lennart; Stansberg, Carl Trygve (Journal article; Peer reviewed, 2018)Recently, a method for numerical reproduction of measured irregular wave events has been developed. The measured motion of the wave maker flaps defines the wave kinematics at the boundary of the numerical simulation in ... -
Efficient Calculation of Spatial and Temporal Evolution of Hydrodynamic Loads on Offshore Wind Substructures
Pakozdi, Csaba; Kamath, Arun; Wang, Weizhi; Martin, Tobias; Bihs, Hans (Chapter, 2021)Estimation of the hydrodynamic loads based on strip theory with the Morrison equation provides a fast and inexpensive method for load estimation for the offshore industry. The advantage of this approach is that it requires ... -
Efficient Wave Modeling Using Non-Hydrostatic Pressure Distribution and Free Surface Tracking on Fixed Grids
Bihs, Hans; Kamath, Arun; Aggarwal, Ankit; Pakozdi, Csaba (Chapter; Peer reviewed, 2018)For the estimation of wave loads on offshore structures, relevant extreme wave events need to be identified. In order to achieve this, long term wave simulations of relatively large scales need to be performed. Computational ... -
A Flexible Fully Nonlinear Potential Flow Model for Wave Propagation over the Complex Topography of the Norwegian Coast
Wang, Weizhi; Pakozdi, Csaba; Kamath, Arun; Fouques, Sebastien; Bihs, Hans (Peer reviewed; Journal article, 2022)Coastal wave propagation and transformation are complicated due to the significant variations of water depth and irregular coastlines, which are typically present at the Norwegian fjords. A potential flow model provides ... -
Fully nonlinear phase-resolved wave modelling in the Norwegian fjords for floating bridges along the E39 coastal highway
Wang, Weizhi; Pakozdi, Csaba; Kamath, Arun; Bihs, Hans (Journal article; Peer reviewed, 2023)Coastal wave conditions are highly influenced by bathymetry variations and coastlines. The Norwegian fjords present large gradients of bathymetry changes and irregular coastline geometries that make the understanding of ... -
A fully nonlinear potential flow wave modelling procedure for simulations of offshore sea states with various wave breaking scenarios
Wang, Weizhi; Pakozdi, Csaba; Kamath, Arun; Bihs, Hans (Peer reviewed; Journal article, 2021)An accurate representation of a given sea state is crucial for the study of hydrodynamic loads on offshore structures. It is straightforward to check the quality of the reproduced regular waves in a numerical wave tank ... -
High-efficiency wind-farm-scale wave force estimation for preliminary design of offshore wind installations
Wang, Weizhi; Kamath, Arun; Pakozdi, Csaba; Bihs, Hans (Chapter, 2022)Many coastal wind farms are subject to a complex hydrodynamic environment due to bathymetry variations and irregular coastlines. The wave height statistical information does not linearly correlate to the wave loads on wind ... -
High-Fidelity Representation of Three-Hour Offshore Short-Crested Wave Field in the Fully Nonlinear Potential Flow Model REEF3D::FNPF
Wang, Weizhi; Pakozdi, Csaba; Kamath, Arun; Bihs, Hans (Chapter, 2020)Stochastic wave properties are crucial for the design of offshore structures. Short-crested seas are commonly seen at the sites of offshore structures, especially during storm events. A long time duration is required in ... -
Hydrodynamic Coupling of Viscous and Non-Viscous Numerical Wave Solutions Within the Open-Source Hydrodynamics Framework REEF3D
Wang, Weizhi; Pakozdi, Csaba; Kamath, Arun; Martin, Tobias; Bihs, Hans (Chapter, 2021)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 ... -
Hydrodynamic Coupling of Viscous and Nonviscous Numerical Wave Solutions Within the Open-Source Hydrodynamics Framework REEF3D
Wang, Weizhi; Pakozdi, Csaba; Kamath, Arun; Martin, Tobias; Bihs, Hans (Peer reviewed; Journal article, 2022)A comprehensive understanding of the marine environment in the offshore area requires phase-resolved wave information. For far-field wave propagation, computational efficiency is crucial, as large spatial and temporal ... -
Investigation of Focusing Wave Properties in a Numerical Wave Tank with a Fully Nonlinear Potential Flow Model
Wang, Weizhi; Kamath, Arun; Pakozdi, Csaba; Bihs, Hans (Journal article; Peer reviewed, 2019)Nonlinear wave interactions and superpositions among the different wave components and wave groups in a random sea sometimes produce rogue waves with extremely large wave heights that appear unexpectedly. A good understanding ... -
Investigation of Higher-Harmonic Wave Forces and Ringing Using CFD Simulations
Kamath, Arun; Bihs, Hans; Pakozdi, Csaba (Chapter, 2018)Typical offshore structures are designed as tension-leg platforms or gravity based structures with cylindrical substructures. The interaction of waves with the vertical cylinders in high sea states can result in a resonant ... -
Numerical Investigation of Irregular Breaking Waves for Extreme Wave Spectra Using CFD
Aggarwal, Ankit; Alagan Chella, Mayilvahanan; Bihs, Hans; Pakozdi, Csaba; Berthelsen, Petter Andreas; Arntsen, Øivind Asgeir (Chapter, 2017)Offshore structures are exposed to irregular sea states. It consists of breaking and non-breaking waves. They experience breaking wave loads perpetually after being installed in the open ocean. Thus, the study of wave ... -
Reduction of the wave propagation error of a sigma grid based numerical tank using a vertical spacing based on the constant truncation error
Pakozdi, Csaba; Wang, Weizhi; Kamath, Arun; Bihs, Hans (Peer reviewed; Journal article, 2021)Numerical wave models that solve the Laplace equation for the velocity potential with a -grid in the vertical direction have been proven to be flexible and efficient. However, it is observed that the dispersion relation ... -
REEF3D Wave Generation Interface for Commercial CFD Codes
Pakozdi, Csaba; Bihs, Hans; Kamath, Arun; Hermundstad, Elin Marita (Chapter, 2019)In recent years CFD developments have shown a trend to combine RANS CFD simulation with other methods such as wave theories or velocity potential based numerical wave tanks, in order to reduce to computation costs. This ...