Browsing NTNU Open by Author "Ommani, Babak"

Now showing items 1-18 of 18

    • 2D experimental and numerical study of moonpool with recess 

      Eriksson, Sebastian Erik (Master thesis, 2018)
      The background for this master's thesis is the complications that is faced in the industry with regards to operational time inside moonpools. This thesis focuses on moonpools with recess, and the fluid resonant phenomena ...

    • A 2D Experimental and Numerical Study of Moonpools With Recess 

      Ravinthrakumar, Senthuran; Kristiansen, Trygve; Ommani, Babak (Chapter, 2018)
      Moonpool resonance is investigated in a two-dimensional setting in terms of regular, forced heave motions of a model with moonpool with different rectangular-shaped recess configurations. A recess is a reduced draft zone ...

    • Application of Continuous Integration in Decision Support and Integrity Management Systems of Offshore Structures 

      Ommani, Babak; Bjermeland, Lasse; Aksnes, Vegard Øgård; Luxcey, Neil; Reinholdtsen, Svein-Arne; Kendon, Timothy Edward (Chapter, 2019)
      Simulation-based decision support systems play an important role in safe operation of offshore floating platforms. These systems, which consist of digital models, simulators, and analysis procedures, are subject to continuous ...

    • Bilge keel induced roll damping of an FPSO with sponsons 

      Ommani, Babak; Fonseca, Nuno; Kristiansen, Trygve; Bakksjø, Hanne (Journal article; Peer reviewed, 2016)
      The bilge keel induced roll damping of an FPSO with sponsons is investigated numerically and experimentally. The influence of the bilge keel size, on the roll damping is studied. Free decay tests of a three-dimensional ...

    • Coupled vessel and moonpool responses in regular and irregular waves 

      Ravinthrakumar, Senthuran; Kristiansen, Trygve; Molin, Bernard Jean Marie; Ommani, Babak (Peer reviewed; Journal article, 2020)
      Hydrodynamic coupling between the ship and moonpool responses is investigated. Dedicated experiments are carried out in the Ocean Basin at Sintef Ocean. Three different moonpool sizes are studied, where the moonpool length ...

    • Hydrodynamic modelling and estimating response of a glacial ice near a drilling rig 

      Ommani, Babak; Berthelsen, Petter Andreas; Lie, Halvor; Aksnes, Vegard Øgård; Løland, Geir (Chapter, 2019)
      Impact scenarios involving a typical drilling rig and glacial ice are studied. The goal is to better identify the important physical effects in modelling the dynamics of glacial ice in presence of waves and a floating ...

    • Investigating a Simplified Model for Moonpool Piston Mode Response in Irregular Waves 

      Ommani, Babak; Kristiansen, Trygve; Berget, Kjetil (Chapter, 2018)
      Estimating moonpool piston mode response at resonance is important for operation safety. This is a difficult task, in particular, due to nonlinear nature of the moonpool response connected to the damping imposed by the ...

    • Investigation of moonpools as pitch motion reducing device 

      Reiersen, Lars Mikkel; Kristiansen, Trygve; Ommani, Babak; Fredriksen, Arnt Gunvald (Peer reviewed; Journal article, 2021)
      Moonpools as a device for reducing pitch motion is investigated experimentally, numerically and by an approximate theory. A two-dimensional study is carried out of a rectangular body with two moonpools. Forced heave and ...

    • Numerical and Experimental Studies of Resonant Flow in Moonpools in Operational Conditions 

      Ravinthrakumar, Senthuran (Doctoral theses at NTNU;2020:152, Doctoral thesis, 2020)
      The present work is relevant for ships with moonpools. A moonpool is a vertical opening through the ship hull, typically used to descend objects into the sea. Model tests and numerical simulations are carried out to ...

    • Numerical Study on Wave Drift Loading on Slender Marine Structures 

      Vadholm, Julie (Master thesis, 2017)
      This master thesis investigates the wave drift forces acting on slender structures through numerical simulations. Basic theory is presented along with an overview of how the problem is treated in the industry and a description ...

    • On Common Research Needs for the Next Generation of Floating Support Structures 

      Aksnes, Vegard Øgård; Alsos, Hagbart Skage; Bachynski-Polic, Erin Elizabeth; Berthelsen, Petter Andreas; Delhaye, Virgile Roger; Furevik, Birgitte Rugaard; Jostad, Hans Petter; Kristiansen, Trygve; Ommani, Babak (Chapter, 2022)

    • A Physical-Based Damping Model of Gap and Moonpool Resonance in WAMIT 

      Ravinthrakumar, Senthuran; Ommani, Babak; Kristiansen, Trygve; Olimb, Idunn; Lyngvær, Bernt Karsten (Chapter, 2022)

    • Potential-Flow Predictions of a Semi-Displacement Vessel Including Applications to Calm-Water Broaching 

      Ommani, Babak (Doktoravhandlinger ved NTNU, 1503-8181; 2013:155, Doctoral thesis, 2013)
      As a marine vehicle’s operational speed increases, hydrodynamic pressure plays an increasingly significant role in carrying the vessel’s weight. The shift of importance from hydrostatic to hydrodynamic pressure may cause ...

    • Sloshing-induced motions of a spar inside a cylindrical dock with baffles in waves 

      Moreau, Mael Korentin Ivan; Kristiansen, Trygve; Ommani, Babak; Molin, Bernard Jean-Marie (Peer reviewed; Journal article, 2023)
      The motions of a free floating offshore wind turbine’s (OWT) spar-type platform inside a bottom-less moored cylindrical dock are investigated for incident wave frequencies near the first lateral sloshing resonance, focusing ...

    • An upright bottomless vertical cylinder with baffles floating in waves 

      Moreau, Mael Korentin Ivan; Kristiansen, Trygve; Ommani, Babak; Molin, Bernard Jean Marie (Peer reviewed; Journal article, 2022)
      Damping of the surge and pitch motions, as well as the first lateral sloshing mode in a rigid free-floating upright circular dock with bilge boxes and open bottom is investigated. Model tests are carried out on a 0.80 m ...

    • Using Neural Networks to Predict the Response of a Floating Structure 

      Bremer, Kaja Steffensen (Master thesis, 2018)
      Floating structures are influenced by the ocean environment which cause responses from the structures known as surge, sway, heave, roll, pitch and yaw. These responses are commonly approximated using linear potential theory, ...

    • Wave inhomogeneities in a wave basin of constant water depth 

      Lafleche, Sebastien Jacques Marie; Ommani, Babak; Kristiansen, Trygve; Fouques, Sebastien (Journal article; Peer reviewed, 2023)
      Experimental testing of large marine structures in hydrodynamic laboratories requires an accurate reproduction of waves over a large area of the basin. However, with a uniform motion of the wavemaker, wave interactions ...

    • Waves' numerical dispersion and damping due to discrete dispersion relation 

      Ommani, Babak; Faltinsen, Odd Magnus (Chapter; Peer reviewed, 2014)
      In linear Rankine panel method, the discrete linear dispersion relation is solved on a discrete free-surface to capture the free-surface waves generated due to wave-body interactions. Discretization introduces numerical ...