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.

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

Vertical Relative Motion Between Two Adjacent Platforms in Oblique Waves

1985 ◽  
Vol 107 (4) ◽  
pp. 455-460 ◽  
Author(s):  
C. H. Kim ◽  
M. C. Fang
Keyword(s):  
Relative Motion ◽  
Hydrodynamic Interaction ◽  
Two Dimensional ◽  
Oblique Waves ◽  
Strip Method ◽  
Strip Theory ◽  
Close Proximity ◽  
Relative Motions

The paper presents a strip theory and its correlation with experiment and analysis on the relative motions of two ships. The ships are in close proximity and in parallel position in oblique waves. The two-dimensional procedure takes account of the hydrodynamic interaction between two cylindrical bodies. It was found that the strip method is a useful technique to predict the hydrodynamically coupled motions of two ships.

Hydrodynamic Interaction of Floating Structure in Regular Waves

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Hassan Abyn ◽  
Adi Maimun ◽  
Jaswar Jaswar ◽  
M. Rafiqul Islam ◽  
Allan Magee ◽  
...  
Keyword(s):  
Hydrodynamic Interaction ◽  
Oil And Gas ◽  
Irregular Waves ◽  
Source Distribution ◽  
Floating Bodies ◽  
Floating Structure ◽  
Distribution Method ◽  
Floating Structures ◽  
Motion Responses ◽  
Hydrodynamics Coefficients

Floating structures play an important role for exploring the oil and gas from the sea. In loading and offloading, motion responses of offshore floating structures are affected through hydrodynamic interaction. Large motions between floating bodies would cause the damage of moorings, offloading system and may colloid to each other. This research studies on hydrodynamic interaction between Tension Leg Platform (TLP) and Semi-Submersible (Tender Assisted Drilling (TAD)) in regular and irregular waves with scenario as follows: fixed TLP and 6-DOF floating semi-submersible and 6-DOF both TLP and semi-submersible. Under these conditions, hydrodynamics coefficients, mooring and connectors forces, motions and relative motions of TLP and Semi-Submersible will be simulated numerically by using 3D source distribution method. As the scope is big, this paper only presents model experiment of floating TLP and semi-submersible in the regular wave. The experiment is carried out in the UTM Towing Tank.

Air Gap Response of Floating Structures: Statistical Predictions Versus Observed Behavior

2001 ◽  
Vol 123 (3) ◽  
pp. 118-123 ◽  
Author(s):  
Steven R. Winterstein ◽  
Bert Sweetman
Keyword(s):  
Diffraction Theory ◽  
Air Gap ◽  
Statistical Analyses ◽  
Irregular Waves ◽  
Wave Crest ◽  
Detailed Model ◽  
Floating Structures ◽  
Amplification Factors ◽  
Wave Elevation ◽  
Time Histories

The air gap response of a specific semi-submersible platform subjected to irregular waves is considered. Detailed model tests for this structure are studied in depth. Using time-histories of both motions and air gap, statistical analyses both for the absolute near-structure wave elevation (with respect to a fixed observer), and the relative wave elevation (with respect to the moving structure) are performed. Statistics of wave crest amplification, due to diffraction, are established. Corresponding amplification factors are derived from linear diffraction theory, and the results of theory and observations are critically compared.

scholarly journals The added mass for two-dimensional floating structures

Wave Motion ◽  
2016 ◽  
Vol 64 ◽  
pp. 1-12 ◽  
Author(s):  
M. McIver ◽  
P. McIver
Keyword(s):  
Added Mass ◽  
Two Dimensional ◽  
Floating Structures

Hydrodynamically Coupled Motions of Two Ships Advancing in Oblique Waves

1986 ◽  
Vol 30 (03) ◽  
pp. 159-171
Author(s):  
M. C. Fang ◽  
C. H. Kim
Keyword(s):  
Integral Equation ◽  
Interaction Effect ◽  
Hydrodynamic Interaction ◽  
Integral Equation Method ◽  
Analytical Investigation ◽  
Rolling Motion ◽  
Two Dimensional ◽  
Oblique Waves ◽  
Slender Bodies ◽  
Wave Induced

An analytical investigation is carried out on the wave-induced motions on two closely spaced, hydrodynamically interacting slender bodies advancing in oblique waves. The two-dimensional procedure, including the hydrodynamic interaction and an integral equation method, is utilized. Numerical results are presented for the coupled motions of two ships. Comparisons are made with the behavior of a monohull and the interaction effect is found to be very important. Different headings and speeds are investigated. It has been found that the rolling motion is reduced while the ships are advancing—a helpful circumstance for cargo transfer between two ships. This study shows that the strip method is a useful technique to predict the hydrodynamically coupled motions between two ships advancing in oblique seas.

scholarly journals Experimental studies on the transformation from firn to ice in the wet-snow zone of temperate glaciers

1997 ◽  
Vol 24 ◽  
pp. 181-185 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada
Keyword(s):  
Experimental Studies ◽  
Ice Formation ◽  
Compression Tests ◽  
Densification Rate ◽  
Overburden Pressure ◽  
Proportionality Constant ◽  
Wet Snow ◽  
Water Saturated ◽  
The Relationship ◽  
Good Agreement

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.

scholarly journals Nonlinear two-dimensional free surface solutions of flow exiting a pipe and impacting a wedge

2021 ◽  
Vol 126 (1) ◽  
Author(s):  
Alex Doak ◽  
Jean-Marc Vanden-Broeck
Keyword(s):  
Surface Tension ◽  
Integral Equation ◽  
Free Surface ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Two Dimensional ◽  
Numerical Schemes ◽  
Additional Advantage ◽  
Infinite Wedge ◽  
Good Agreement

AbstractThis paper concerns the flow of fluid exiting a two-dimensional pipe and impacting an infinite wedge. Where the flow leaves the pipe there is a free surface between the fluid and a passive gas. The model is a generalisation of both plane bubbles and flow impacting a flat plate. In the absence of gravity and surface tension, an exact free streamline solution is derived. We also construct two numerical schemes to compute solutions with the inclusion of surface tension and gravity. The first method involves mapping the flow to the lower half-plane, where an integral equation concerning only boundary values is derived. This integral equation is solved numerically. The second method involves conformally mapping the flow domain onto a unit disc in the s-plane. The unknowns are then expressed as a power series in s. The series is truncated, and the coefficients are solved numerically. The boundary integral method has the additional advantage that it allows for solutions with waves in the far-field, as discussed later. Good agreement between the two numerical methods and the exact free streamline solution provides a check on the numerical schemes.

scholarly journals Template-Free Self-Assembly of Two-Dimensional Polymers into Nano/Microstructured Materials

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3310
Author(s):  
Shengda Liu ◽  
Jiayun Xu ◽  
Xiumei Li ◽  
Tengfei Yan ◽  
Shuangjiang Yu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Recent Progress ◽  
Two Dimensional ◽  
Subsequent Removal ◽  
The Past ◽  
2D Polymers ◽  
Template Free ◽  
Self Assembled ◽  
The Relationship ◽  
Polymer Tubes

In the past few decades, enormous efforts have been made to synthesize covalent polymer nano/microstructured materials with specific morphologies, due to the relationship between their structures and functions. Up to now, the formation of most of these structures often requires either templates or preorganization in order to construct a specific structure before, and then the subsequent removal of previous templates to form a desired structure, on account of the lack of “self-error-correcting” properties of reversible interactions in polymers. The above processes are time-consuming and tedious. A template-free, self-assembled strategy as a “bottom-up” route to fabricate well-defined nano/microstructures remains a challenge. Herein, we introduce the recent progress in template-free, self-assembled nano/microstructures formed by covalent two-dimensional (2D) polymers, such as polymer capsules, polymer films, polymer tubes and polymer rings.

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