Deformation of the Two-dimensional Low-frequency Wave Spectrum in the Shallow Water Region

1988 ◽  
pp. 331-338
Author(s):  
A. Kimura
Keyword(s):  
Shallow Water ◽  
Wave Spectrum ◽  
Low Frequency ◽  
Two Dimensional ◽  
Frequency Wave ◽  
Water Region ◽  
Shallow Water Region

Second-Order Low-Frequency Wave Forces on a SPM Offloading Tanker in Shallow Water

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
S. Ma ◽  
M. H. Kim ◽  
S. Shi
Keyword(s):  
Shallow Water ◽  
Transfer Functions ◽  
Low Frequency ◽  
Wave Force ◽  
Second Order ◽  
Irregular Waves ◽  
Mooring Line ◽  
Frequency Wave ◽  
Water Region ◽  
Shallow Water Region

This paper studies the influence of three different calculation methods of the second-order low-frequency (LF) wave-force quadratic transfer functions (QTFs) for a single point mooring (SPM) tanker system in relatively shallow water region. The multivessel-mooring hawser coupled dynamic analysis is used to simulate the floater relative motions and mooring and hawser tensions. Because the SPM tanker is deployed in shallow water region and the slowly varying drift motions are to be dominant in typical operational conditions, the accurate calculation of LF wave-force QTFs become important especially for mooring and hawser-tension prediction. The practically popular Newman’s approximation and another approximation excluding complicated free-surface integrals are used to calculate the LF QTFs on the offloading tanker and they are compared with the complete QTF results. Further comparison is carried out by calculating the resulting LF wave-force spectra and motion time histories and analyzing their impacts on hawser and mooring line tensions. Through the example studies, the limitation of the Newman’s approximation in the case of shallow water and longer period irregular waves is underscored.

Low Frequency Wave Forces and Wave Induced Motions of a FPSO in Shallow Water

2007 ◽  
Author(s):  
Longfei Xiao ◽  
Jianmin Yang ◽  
Zhiqiang Hu
Keyword(s):  
Shallow Water ◽  
Wave Spectrum ◽  
Low Frequency ◽  
Wave Force ◽  
Wave Forces ◽  
Frequency Wave ◽  
Wave Basin ◽  
The Difference ◽  
The One ◽  
Wave Induced

The low frequency (LF) response of a soft yoke moored 160kDWT FPSO in shallow water is investigated by conducting frequency domain computations and wave basin model tests. An incident wave with Hs = 4.1m and Tp = 8.9s is applied. An obvious LF part appears in the measured wave spectrum at water depth of 16.7m. As a result, the 1st order LF wave force exists and is much larger than the 2nd one. The difference of the spectrums is about one hundred times. The LF wave drift force increases enormously. Consequently, much larger resonant surge response is induced. The LF surge amplitude at h = 16.7m is about 7 times the one at h = 29.0m and 9 times the one in deep water, although the 2nd order response changes a little. Therefore, in very shallow water, LF part of incident waves should be taken into account carefully and LF wave forces and wave induced motions will be very serious.

GEK measurements in a shallow water region

1981 ◽  
Vol 37 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Yutaka Nagata ◽  
Kimie Yonemura ◽  
Hideo Nishida
Keyword(s):  
Shallow Water ◽  
Water Region ◽  
Shallow Water Region

Bathymetry Estimation Using Aerial Imagery for Shallow Water Region

2016 ◽  
Vol 16 (5) ◽  
Author(s):  
Jin-Hak Yi ◽  
◽  
Kyong-Ho Ryu ◽  
Changjoo Shin ◽  
Won-Dae Baek ◽  
...  
Keyword(s):  
Shallow Water ◽  
Aerial Imagery ◽  
Water Region ◽  
Shallow Water Region

Bathymetry survey using an aerial image for a very shallow water region

2016 ◽  
Author(s):  
Jin-Hak Yi ◽  
Chang-Joo Shin ◽  
Kyong-Ho Ryu ◽  
Weon Mu Jeong
Keyword(s):  
Shallow Water ◽  
Aerial Image ◽  
Water Region ◽  
Shallow Water Region
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