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We present a novel convex optimisation model for ship speed profile optimisation under varying environmental conditions, with a fixed schedule for the journey. To demonstrate the efficacy of the proposed method, a combined speed profile optimisation model was developed that employed an existing dynamic programming approach, along the novel convex optimisation model. The proposed model was tested with 5 different ships for 20 journeys from Houston, Texas to London Gateway, with differing environmental conditions, which were retrieved from actual weather forecasts. As a result, it was shown that the combined model with both dynamic programming and convex optimisation was approximately 22% more effective in developing a fuel saving speed profile compared to dynamic programming alone. Overall, average fuel savings for the studied voyages with speed profile optimisation was approximately 1.1% compared to operation with a fixed speed and 3.5% for voyages where significant variance in environmental conditions was present. Speed profile optimisation was found to be especially beneficial in cases where detrimental environmental conditions could be avoided with minor speed adjustments. Relaxation of the fixed schedule constraint likely leads to larger savings but makes comparison virtually impossible as a lower speed leads to lower propulsion energy needed.
Janne Huotari; Teemu Manderbacka; Antti Ritari; Kari Tammi. Convex Optimisation Model for Ship Speed Profile: Optimisation under Fixed Schedule. Journal of Marine Science and Engineering 2021, 9, 730 .
AMA StyleJanne Huotari, Teemu Manderbacka, Antti Ritari, Kari Tammi. Convex Optimisation Model for Ship Speed Profile: Optimisation under Fixed Schedule. Journal of Marine Science and Engineering. 2021; 9 (7):730.
Chicago/Turabian StyleJanne Huotari; Teemu Manderbacka; Antti Ritari; Kari Tammi. 2021. "Convex Optimisation Model for Ship Speed Profile: Optimisation under Fixed Schedule." Journal of Marine Science and Engineering 9, no. 7: 730.
Teemu Manderbacka; Nikolaos Themelis; Igor Bačkalov; Evangelos Boulougouris; Eleftheria Eliopoulou; Hirotada Hashimoto; Dimitrios Konovessis; Jean-François Leguen; Marcos Míguez González; Claudio A. Rodríguez; Anders Rosén; Pekka Ruponen; Vladimir Shigunov; Martin Schreuder; Daisuke Terada. An overview of the current research on stability of ships and ocean vehicles: The STAB2018 perspective. Ocean Engineering 2019, 186, 106090 .
AMA StyleTeemu Manderbacka, Nikolaos Themelis, Igor Bačkalov, Evangelos Boulougouris, Eleftheria Eliopoulou, Hirotada Hashimoto, Dimitrios Konovessis, Jean-François Leguen, Marcos Míguez González, Claudio A. Rodríguez, Anders Rosén, Pekka Ruponen, Vladimir Shigunov, Martin Schreuder, Daisuke Terada. An overview of the current research on stability of ships and ocean vehicles: The STAB2018 perspective. Ocean Engineering. 2019; 186 ():106090.
Chicago/Turabian StyleTeemu Manderbacka; Nikolaos Themelis; Igor Bačkalov; Evangelos Boulougouris; Eleftheria Eliopoulou; Hirotada Hashimoto; Dimitrios Konovessis; Jean-François Leguen; Marcos Míguez González; Claudio A. Rodríguez; Anders Rosén; Pekka Ruponen; Vladimir Shigunov; Martin Schreuder; Daisuke Terada. 2019. "An overview of the current research on stability of ships and ocean vehicles: The STAB2018 perspective." Ocean Engineering 186, no. : 106090.
The current damage stability criteria for ships are mainly based on the characteristics of the righting lever curve. The related calculations for different intermediate stages during the flooding process, and for the final equilibrium condition, are generally considered trivial. However, with the increased computing capacity the regulations are developing towards a more realistic assessment of the intermediate stages of flooding. Most notably, time-domain flooding simulation has become a viable option. Consequently, the practices and assumptions related to the calculation of the righting lever curve for a damaged ship need to be addressed. This paper presents these challenges from different perspectives, and reviews available numerical methods for assessment of damage stability. Sample calculation results with different methods are presented for various damage scenarios, and the results are thoroughly analyzed and discussed. Finally, some recommendations on using the different methods are given.
Pekka Ruponen; Teemu Manderbacka; Daniel Lindroth. On the calculation of the righting lever curve for a damaged ship. Ocean Engineering 2018, 149, 313 -324.
AMA StylePekka Ruponen, Teemu Manderbacka, Daniel Lindroth. On the calculation of the righting lever curve for a damaged ship. Ocean Engineering. 2018; 149 ():313-324.
Chicago/Turabian StylePekka Ruponen; Teemu Manderbacka; Daniel Lindroth. 2018. "On the calculation of the righting lever curve for a damaged ship." Ocean Engineering 149, no. : 313-324.
Dynamics of an abrupt flooding case are studied by comparing fully dynamic and quasi-static flooding simulation methods. Transient asymmetric flooding is traditionally modelled by dividing the compartment into smaller parts with bulkheads representing different obstructions in the flooded compartment. The implications of this assumption are studied by varying the size of the opening on the dividing bulkhead. The importance of the inflooding jet to the response is shown. The jet i.e. the inflooding momentum flux is modelled as force acting on the lumped mass. When the flooded compartment does not have significant obstructions it is important to account for the inflooding momentum flux.
Teemu Manderbacka; Pekka Ruponen. The impact of the inflow momentum on the transient roll response of a damaged ship. Ocean Engineering 2016, 120, 346 -352.
AMA StyleTeemu Manderbacka, Pekka Ruponen. The impact of the inflow momentum on the transient roll response of a damaged ship. Ocean Engineering. 2016; 120 ():346-352.
Chicago/Turabian StyleTeemu Manderbacka; Pekka Ruponen. 2016. "The impact of the inflow momentum on the transient roll response of a damaged ship." Ocean Engineering 120, no. : 346-352.
In the present paper, 2D numerical simulation of sloshing waves coupled to the flooding flow between two compartments is carried out employing lumped mass and Lagrangian methods. The first method used is a Lumped Mass method with a moving free surface (LM), which is based on the motion equations for the gravity centre of mass within a compartment. In this method, the free surface is modelled as a planar surface, with limited degrees of freedom. The second one is the so-called Moving Particle Semi-Implicit (MPS) method, a robust method based on particle interactions in a Lagrangian coordinate system. Sloshing simulations are performed within a closed domain, in which the free surface is modelled as a deformable surface for a single-phase flow. An improved boundary wall condition scheme is applied. By applying these two methods the hydrodynamic features of the sloshing flow under sway and roll motion and several water levels are investigated. The excitation frequencies are set near the natural wave frequencies. Furthermore, the complexity added to the sloshing wave by the flow exchange passing through an opening are reported, taking into account two opening configurations. The numerical results are validated by corresponding experimental data. Comparison of the numerical results against the experimental data shows, in general, good agreement. Two main stages of accuracy levels are observed for lower and higher frequencies. At the first stage, the Lumped Mass and the Moving Particle Semi-Implicit methods present similar results, whereas at the last stage the MPS model is seen to be more suitable for the sloshing simulations, in which wave breaking is the dominant phenomenon.
J.M. Fonfach; Teemu Manderbacka; M.A.S. Neves. Numerical sloshing simulations: Comparison between lagrangian and lumped mass models applied to two compartments with mass transfer. Ocean Engineering 2016, 114, 168 -184.
AMA StyleJ.M. Fonfach, Teemu Manderbacka, M.A.S. Neves. Numerical sloshing simulations: Comparison between lagrangian and lumped mass models applied to two compartments with mass transfer. Ocean Engineering. 2016; 114 ():168-184.
Chicago/Turabian StyleJ.M. Fonfach; Teemu Manderbacka; M.A.S. Neves. 2016. "Numerical sloshing simulations: Comparison between lagrangian and lumped mass models applied to two compartments with mass transfer." Ocean Engineering 114, no. : 168-184.
Numerical non-linear time domain simulation method for damaged ship motionsis presented. Floodwater motion modelling is based on the lumpedmass method with a moving free surface. The ship and floodwater motionsare fully coupled. The variation of the floodwater mass is accounted for. Amodel to account for the flooding ingress transporting the momentum is presented.The experiments of abrupt flooding have shown that the ship mayexperience the first large roll towards the undamaged side, especially when alarge undivided compartment is flooded. The presented time domain modelis validated against the experimental data on the roll damping of the floodedship and transient flooding. Two different initial stability conditions andtwo different compartment layouts are studied. Viscous dissipation of thefloodwater motions is modelled with an equivalent friction coefficient. Theimpact of the viscous damping is studied. Transient flooding tests show thatthe inflow momentum has to be accounted for when the undivided compartment is flooded. The simulation model is capable of capturing the impact of the inflooding jet and the first roll on the opposite side of the damage is reproduced.Peer reviewe
Teemu Manderbacka; Tommi Mikkola; Pekka Ruponen; Jerzy Matusiak. Transient response of a ship to an abrupt flooding accounting for the momentum flux. Journal of Fluids and Structures 2015, 57, 108 -126.
AMA StyleTeemu Manderbacka, Tommi Mikkola, Pekka Ruponen, Jerzy Matusiak. Transient response of a ship to an abrupt flooding accounting for the momentum flux. Journal of Fluids and Structures. 2015; 57 ():108-126.
Chicago/Turabian StyleTeemu Manderbacka; Tommi Mikkola; Pekka Ruponen; Jerzy Matusiak. 2015. "Transient response of a ship to an abrupt flooding accounting for the momentum flux." Journal of Fluids and Structures 57, no. : 108-126.
Teemu Manderbacka; Pekka Ruponen; Jakke Kulovesi; Jerzy Matusiak. Model experiments of the transient response to flooding of the box shaped barge. Journal of Fluids and Structures 2015, 57, 127 -143.
AMA StyleTeemu Manderbacka, Pekka Ruponen, Jakke Kulovesi, Jerzy Matusiak. Model experiments of the transient response to flooding of the box shaped barge. Journal of Fluids and Structures. 2015; 57 ():127-143.
Chicago/Turabian StyleTeemu Manderbacka; Pekka Ruponen; Jakke Kulovesi; Jerzy Matusiak. 2015. "Model experiments of the transient response to flooding of the box shaped barge." Journal of Fluids and Structures 57, no. : 127-143.
Teemu Manderbacka; J. Kulovesi; M.A.C. Celis; J.E. Matusiak; M.A.S. Neves. Model tests on the impact of the opening location on the water motions in a flooded tank with two compartments. Ocean Engineering 2014, 84, 67 -80.
AMA StyleTeemu Manderbacka, J. Kulovesi, M.A.C. Celis, J.E. Matusiak, M.A.S. Neves. Model tests on the impact of the opening location on the water motions in a flooded tank with two compartments. Ocean Engineering. 2014; 84 ():67-80.
Chicago/Turabian StyleTeemu Manderbacka; J. Kulovesi; M.A.C. Celis; J.E. Matusiak; M.A.S. Neves. 2014. "Model tests on the impact of the opening location on the water motions in a flooded tank with two compartments." Ocean Engineering 84, no. : 67-80.
Two different methods, pendulum model and computational fluid dynamics (CFD), to predict the forces on the ship caused by the flooded water are compared against the model test results. Calculations were performed for a tank in forced motions at different frequencies, for which experimental results were available. The tank had a dividing wall with an opening. The overall behaviour of the force time history was well captured with the pendulum model. In particular at lower frequency the agreement of the force range is very good. Some small force peaks due to the sloshing were predicted in a good correspondence with the CFD simulations. At a higher frequency slight discrepancy is shown also in the CFD calculations. The free surface behaviour is captured in detailed level by the CFD calculations, but the overall motion of the water is captured also with the pendulum model with plane surface model. Comparison to the model tests shows the applicability of the pendulum model in simulating sloshing case with the exchange of water between the compartments. These comparisons show that the pendulum model is a sufficiently accurate and calculation time wise efficient method. It provides a tool to perform a great amount of simulations in order to study the impact of different parameters and the statistical probabilities of ship survival under different accident scenarios.
Teemu Manderbacka; Vincent Jacob; Thomas Carriot; Tommi Mikkola; Jerzy E. Matusiak. Sloshing Forces on a Tank With Two Compartments, Application of the Pendulum Model and CFD. Volume 3: Offshore Geotechnics 2014, 1 .
AMA StyleTeemu Manderbacka, Vincent Jacob, Thomas Carriot, Tommi Mikkola, Jerzy E. Matusiak. Sloshing Forces on a Tank With Two Compartments, Application of the Pendulum Model and CFD. Volume 3: Offshore Geotechnics. 2014; ():1.
Chicago/Turabian StyleTeemu Manderbacka; Vincent Jacob; Thomas Carriot; Tommi Mikkola; Jerzy E. Matusiak. 2014. "Sloshing Forces on a Tank With Two Compartments, Application of the Pendulum Model and CFD." Volume 3: Offshore Geotechnics , no. : 1.
Model tests to generate validation data for the codes predicting the sloshing and progression of water through an opening in case of a damaged ship were planned and performed. Behaviour of the flooding water after the damage is greatly dependent on the internal compartment geometries and vessel motions. Vessels angular position and motions in turn are affected by the flooding water. Thus accurate prediction of this strongly coupled flooding phenomenon requires simultaneous solving of the ship motions and behaviour of the internal water. In order to produce validation data for calculation methods for internal flood water behaviour, tests for water motion between two connected neighbouring compartments were designed. Model tests concentrated purely on the internal sloshing motion under forced compartment motions, thus uncoupling the vessel response.
Teemu Manderbacka; Marcelo Vitola; Miguel A. Celis C.; Jerzy E. Matusiak; Marcelo A. S. Neves; Paulo De Tarso Esperanca. Influence of Sloshing on the Transfer of Water Between Neighbouring Compartments Considering Three Different Opening Configurations. Volume 9: Odd M. Faltinsen Honoring Symposium on Marine Hydrodynamics 2013, 1 .
AMA StyleTeemu Manderbacka, Marcelo Vitola, Miguel A. Celis C., Jerzy E. Matusiak, Marcelo A. S. Neves, Paulo De Tarso Esperanca. Influence of Sloshing on the Transfer of Water Between Neighbouring Compartments Considering Three Different Opening Configurations. Volume 9: Odd M. Faltinsen Honoring Symposium on Marine Hydrodynamics. 2013; ():1.
Chicago/Turabian StyleTeemu Manderbacka; Marcelo Vitola; Miguel A. Celis C.; Jerzy E. Matusiak; Marcelo A. S. Neves; Paulo De Tarso Esperanca. 2013. "Influence of Sloshing on the Transfer of Water Between Neighbouring Compartments Considering Three Different Opening Configurations." Volume 9: Odd M. Faltinsen Honoring Symposium on Marine Hydrodynamics , no. : 1.