scholarly journals Hydrodynamic Interaction Effects on Wave Exciting Force in Large Scale Floating Structures

1993 ◽  
Vol 1993 (174) ◽  
pp. 243-251 ◽  
Author(s):  
Koichiro Yoshida ◽  
Hideyuki Suzuki ◽  
Noriaki Oka ◽  
Kazuhiro Iijima ◽  
Takuya Shimura ◽  
...  
Keyword(s):  
Large Scale ◽  
Hydrodynamic Interaction ◽  
Interaction Effects ◽  
Exciting Force ◽  
Floating Structures

The Motions of Adjacent Floating Structures in Oblique Waves

1984 ◽  
Vol 106 (2) ◽  
pp. 199-205 ◽  
Author(s):  
N. Kodan
Keyword(s):  
Hydrodynamic Interaction ◽  
Diffraction Theory ◽  
Added Mass ◽  
Exciting Force ◽  
Irregular Waves ◽  
Two Dimensional ◽  
Oblique Waves ◽  
Floating Structures ◽  
The Relationship ◽  
Good Agreement

This paper describes the theory on the effects of hydrodynamic interaction between two parallel slender structures in oblique waves. The method is based on the two-dimensional diffraction theory including the interaction effect. According to Ohkusu’s theory, the sectional interaction effects on the added mass, damping coefficient and wave exciting force are evaluated by analyzing incoming waves generated by the oscillatory motion of corresponding sections. Numerical results of the wave exciting force and moment and motions for the case of a combination of a ship and a rectangular barge are presented and compared with the results from model experiments. The comparison shows good agreement. Finally, some attention is given to the relationship between the arrangement of the two structures and responses in irregular waves.

A Numerically Efficient Method for Analysis of Very Large Articulated Floating Structures

1998 ◽  
Vol 42 (03) ◽  
pp. 174-186
Author(s):  
C. J. Garrison
Keyword(s):  
Hydrodynamic Interaction ◽  
Near Field ◽  
Three Dimensional ◽  
Computational Effort ◽  
Floating Structure ◽  
Complete Structure ◽  
Field Interaction ◽  
Floating Structures ◽  
Computing Effort ◽  
The Individual

A method is presented for evaluation of the motion of long structures composed of interconnected barges, or modules, of arbitrary shape. Such structures are being proposed in the construction of offshore airports or other large offshore floating structures. It is known that the evaluation of the motion of jointed or otherwise interconnected modules which make up a long floating structure may be evaluated by three dimensional radiation/diffraction analysis. However, the computing effort increases rapidly as the complexity of the geometric shape of the individual modules and the total number of modules increases. This paper describes an approximate method which drastically reduces the computational effort without major effects on accuracy. The method relies on accounting for hydrodynamic interaction effects between only adjacent modules within the structure rather than between all of the modules since the near-field interaction is by far the more important. This approximation reduces the computational effort to that of solving the two-module problem regardless of the total number of modules in the complete structure.

Theoretical Study on Hydroelastic Responses of Very Large Floating Structures Near Islands and Reefs

2014 ◽  
Author(s):  
Chao Tian ◽  
Xinyun Ni ◽  
Jun Ding ◽  
Peng Yang ◽  
Yousheng Wu
Keyword(s):  
Large Scale ◽  
Oil And Gas ◽  
Linear Equations ◽  
Dynamic Responses ◽  
Wave Loads ◽  
Structural Dynamic ◽  
Floating Structures ◽  
Geological Conditions ◽  
Incident Waves ◽  
Very Large Floating Structures

In order to explore the fishery, oil and gas, and tourism resources in the ocean, Very Large Floating Structures (VLFS) can be deployed near islands and reefs as a logistic base with various functions such as a floating harbor, accommodation, fishery processing, oil and gas exploration, environment surveillance, airplane landing and taking off, etc. However, in addition to the complicated hydroelastic coupling effects between the hydrodynamic loads and structural dynamic responses, when tackling the hydroelastic problems of floating structures deployed near islands and reefs, several other environmental effects and numerical techniques should be taken into account: 1) The influences of the non-uniform incident waves (multi-directions, different wave frequencies); 2) Complex seabed profile and its impact on the incident waves; 3) Nonlinear second order wave exciting forces in the complex mooring system, shallow water and coral reef geological conditions; 4) Parallel computing technology and fast solving methods for the large scale linear equations, accounting for the influence of dramatic increase of number of meshes to the computation efforts and efficiency. In the present paper the theoretical investigation on the hydroelastic responses of VLFS deployed near islands and reefs has been presented. In addition, based on the pulsating source Green function, the high performance parallel fast computing techniques and other numerical methods, in solving large scale linear equations, have been introduced in the three-dimensional hydroelastic analysis package THAFTS. The motions, wave loads, distortions and stresses can be calculated using the present theoretical model and the results can be used in the design and safety assessment of VLFS.

scholarly journals Large-scale multivariate multi-ancestry Interaction analyses point towards different genetic mechanisms by population and exposure

2019 ◽  
Author(s):  
Vincent Laville ◽  
Timothy Majarian ◽  
Yun J Sung ◽  
Karen Schwander ◽  
Mary F Feitosa ◽  
...  
Keyword(s):  
Complex Traits ◽  
Large Scale ◽  
Biological Significance ◽  
Genetic Effect ◽  
Cell Types ◽  
Interaction Effects ◽  
Phenotypic Variance ◽  
Genetic Associations ◽  
Genetic Heritability ◽  
Meta Analyses

AbstractTheCHARGE Gene-Lifestyle Interactions Working Groupis a unique initiative formed to improve our understanding of the role and biological significance of gene-environment interactions in human traits and diseases. The consortium published several multi-ancestry genome-wide interaction studies (GWIS) involving up to 610,475 individuals for three lipids and four blood pressure traits while accounting for interaction effects with drinking and smoking exposures. Here we used GWIS summary statistics from these studies to decipher potential differences in genetic associations and GxE interactions across phenotype-exposure-population trios, and to derive new insights on the potential mechanistic underlying GxE through in-silico functional analyses. Our comparative analysis shows first that interaction effects likely contribute to the commonly reported ancestry-specific genetic effect in complex traits, and second, that some phenotype-exposures pairs are more likely to benefit from a greater detection power when accounting for interactions. It also highlighted a negligible correlation between main and interaction effects, providing material for future methodological development and biological discussions. We also estimated contributions to phenotypic variance, including in particular the genetic heritability conditional on the exposure, and heritability partitioned across a range of functional annotations and cell-types. In these analyses, we found multiple instances of heterogeneity of functional partitions between exposed and unexposed individuals, providing new evidence for likely exposure-specific genetic pathways. Finally, along this work we identified potential biases in methods used to jointly meta-analyses genetic and interaction effects. We performed a series of simulations to characterize these limitations and to provide the community with guideline for future GxE studies.

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