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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Ocean Systems Engineering
Journal Basic Information
Journal DOI :
Editor in Chief :
Young S. Shin
Volume & Issues
Volume 5, Issue 4 - Dec 2015
Volume 5, Issue 3 - Sep 2015
Volume 5, Issue 2 - Jun 2015
Volume 5, Issue 1 - Mar 2015
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Numerical simulation of wave slamming on 3D offshore platform deck using a coupled Level-Set and Volume-of-Fluid method for overset grid system
Zhao, Yucheng ; Chen, Hamn-Ching ; Yu, Xiaochuan ;
Ocean Systems Engineering, volume 5, issue 4, 2015, Pages 245~259
DOI : 10.12989/ose.2015.5.4.245
The numerical simulation of wave slamming on a 3D platform deck was investigated using a coupled Level-Set and Volume-of-Fluid (CLSVOF) method for overset grid system incorporated into the Finite-Analytic Navier-Stokes (FANS) method. The predicted slamming impact forces were compared with the corresponding experimental data. The comparisons showed that the CLSVOF method is capable of accurately predicting the slamming impact and capturing the violent free surface flow including wave slamming, wave inundation and wave recession. Moreover, the capability of the present CLSVOF method for overset grid system is a prominent feature to handle the prediction of wave slamming on offshore structure.
Numerical modeling of internal waves within a coupled analysis framework and their influence on spar platforms
Kurup, Nishu V. ; Shi, Shan ; Jiang, Lei ; Kim, M.H. ;
Ocean Systems Engineering, volume 5, issue 4, 2015, Pages 261~277
DOI : 10.12989/ose.2015.5.4.261
Internal solitary waves occur due to density stratification and are nonlinear in nature. These waves have been observed in many parts of the world including the South China Sea, Andaman Sea and Sulu Sea. Their effect on floating systems has been an emerging field of interest and recent offshore developments in the South China Sea where several offshore oil and gas discoveries are located have confirmed adverse effects including large platform motions and riser system damage. A valid numerical model conforming to the physics of internal waves is implemented in this paper and the effect on a spar platform is studied. The physics of internal waves is modeled by the Korteweg-de Vries (KdV) equation, which has a general solution involving Jacobian elliptical functions. The effects of vertical density stratification are captured by solving the Taylor Goldstein equation. Fully coupled time domain analyses are conducted to estimate the effect of internal waves on a typical truss spar, which is configured to South China Sea development requirements and environmental conditions. The hull, moorings and risers are considered as an integrated system and the platform global motions are analyzed. The study could be useful for future guidance and development of offshore systems in the South China Sea and other areas where the internal wave phenomenon is prominent.
Analytical study of the failure mode and pullout capacity of suction anchors in sand
Liu, Haixiao ; Peng, Jinsong ; Zhao, Yanbing ;
Ocean Systems Engineering, volume 5, issue 4, 2015, Pages 279~299
DOI : 10.12989/ose.2015.5.4.279
Suction anchors are widely adopted and play an important role in mooring systems. However, how to reliably predict the failure mode and ultimate pullout capacity of the anchor in sand, especially by an easy-to-use theoretical method, is still a great challenge. Existing methods for predicting the inclined pullout capacity of suction anchors in sand are mainly based on experiments or finite element analysis. In the present work, based on a rational mechanical model for suction anchors and the failure mechanism of the anchor in the seabed, an analytical model is developed which can predict the failure mode and ultimate pullout capacity of suction anchors in sand under inclined loading. Detailed parametric analysis is performed to explore the effects of different parameters on the failure mode and ultimate pullout capacity of the anchor. To examine the present model, the results from experiments and finite element analysis are employed to compare with the theoretical predictions, and a general agreement is obtained. An analytical method that can evaluate the optimal position of the attachment point is also proposed in the present study. The present work demonstrates that the failure mode and pullout capacity of suction anchors in sand can be easily and reasonably predicted by the theoretical model, which might be a useful supplement to the experimental and numerical methods in analyzing the behavior of suction anchors.
A shell-dynamics model for marine pipelines of large suspended length
Katifeoglou, Stefanos A. ; Chatjigeorgiou, Ioannis K. ;
Ocean Systems Engineering, volume 5, issue 4, 2015, Pages 301~318
DOI : 10.12989/ose.2015.5.4.301
The present investigations introduce the shell-finite element discretization for the dynamics of slender marine pipelines. A long catenary pipeline, corresponding to a particular Steel Catenary Riser (SCR), is investigated under long-standing cyclic loading. The long structure is divided into smaller tubular parts which are discretized with 8-node planar shell elements. The transient analysis of each part is carried out by the implicit time integration scheme, within a Finite Elements (FE) solver. The time varying external loads and boundary conditions on each part are the results of a prior solution of an integrated line-dynamics model. The celebrated FE approximation can produce a more detailed stress distribution along the structural surface than the simplistic "line-dynamics" approach.
Effects of discontinuous submerged breakwater on water surface elevation
Ketabdari, Mohammad J. ; lamouki, Mohammad Barzegar Paiin ; Moghaddasi, Alireza ;
Ocean Systems Engineering, volume 5, issue 4, 2015, Pages 319~329
DOI : 10.12989/ose.2015.5.4.319
Submerged breakwaters are used to prevent shore line erosion and sediment transportation. One of their advantages is low visual impact. In this paper, the effects of discontinuous submerged breakwaters over water surface elevation was numerically studied considering the extended Boussinesq equations as governing equations using MIKE21 software. The result of discontinuous breakwater was compared with a beach without breakwater. The results showed that the gap dramatically effects on surface elevation from shore line to offshore. It is also evident from results that with approaching the center of the gap, fluctuation of surface elevation is generated. It is because of passing longshore currents towards offshore through the gap which leads to an increase in sediment transportation rate. Nevertheless, transferring water mass from breakwater gap results in powerful rip currents leading to high changes on longshore wave profile.