Motion Responses of High Speed Vessels in Regular and Random Waves

2000 ◽  
Author(s):  
Yonghwan Kim ◽  
◽  
Kenneth M Weems ◽  
Keyword(s):  
High Speed ◽  
Random Waves ◽  
Motion Responses ◽  
Regular And Random Waves

Steady-State and Transient Dynamical Systems Analysis of Uncoupled and Coupled Very Large Amplitude Roll Response of a Vessel in Regular and Random Waves

2006 ◽  
Author(s):  
Jeffrey M. Falzarano ◽  
Srinivas Vishnubhotla ◽  
Sarah E. Juckett
Keyword(s):  
Steady State ◽  
Stability Analysis ◽  
Dynamical Systems ◽  
Large Amplitude ◽  
Early Stage ◽  
Static Stability ◽  
Random Waves ◽  
The Us ◽  
Us Navy ◽  
Regular And Random Waves

This paper contains the most recent results of our analysis of the DTMB 5415 model hull. This hull is an early stage version of the US Navy’s DDG-51 and approximately represents the last traditional destroyer hull form designed, built and operated by the US Navy. Moreover, the US Navy has recently proposed an alternative simulation based approach to traditional static stability analysis for advanced hull forms. Static stability analysis has been in use by the US Navy for at least 50 years. This paper proposes an alternative analysis technique which uses modern techniques of dynamical systems to analyze the large amplitude (nonlinear) roll response of a vessel in waves. The technique considers the steady state (local) roll response, the transient (global) roll response in both regular and random waves. Moreover, the effects of coupling, damping and reduced GM are all investigated.

Comparison of Analyses for Moored Systems in Random Waves

1987 ◽  
Vol 109 (2) ◽  
pp. 133-141
Author(s):  
R. Eatock Taylor ◽  
P. Sincock
Keyword(s):  
Transfer Functions ◽  
Probability Distributions ◽  
Low Frequency ◽  
Response Probability ◽  
Random Waves ◽  
Frequency Spectra ◽  
Frequency Wave ◽  
Strongly Nonlinear ◽  
Motion Responses ◽  
Wave Drift Forces

This paper investigates methods of simulating the combined wave frequency and low-frequency wave drift forces and motion responses of floating systems. This is motivated by the requirement for estimates of response statistics for systems on nonlinear moorings. Results are given for a linear system for which experimental data are available (an articulated column model); and for a moored barge on mildly and strongly nonlinear moorings. Estimates are obtained for low-frequency spectra, linear and quadratic transfer functions, response probability distributions, and peak distributions.

scholarly journals Numerical Simulation of Seakeeping Performance on the Preliminary Design of a Semi-Planing Craft

2019 ◽  
Vol 7 (7) ◽  
pp. 199 ◽  
Author(s):  
Yu-Hsien Lin ◽  
Chia-Wei Lin
Keyword(s):  
High Speed ◽  
Route Planning ◽  
Test Cases ◽  
Preliminary Design ◽  
Sea State ◽  
Planing Craft ◽  
High Speeds ◽  
Motion Responses ◽  
Seakeeping Performance ◽  
The Difference

This study established a seakeeping program to evaluate the motion responses of a high speed semi-planing craft and to develop a database for future route planning. A series 62 mono-hull was chosen for the test cases, comparing seakeeping performances with full-scale on-board measurements. The statistical results were obtained using spectral analysis, which combines the International Towing Tank Conference (ITTC) spectrum with the response amplitude operator (RAO) responses of each wave heading for a given sailing speed. The speed polar diagram was made to illustrate five degree-of-freedom (DOF) motion responses between sailing speeds and wave heading angles in a particular sea state. Although the craft has different trim angles at high speeds (because of dynamic lift) under various loading and draft conditions, this study only investigated the trim angles of 0° (even keel), 1° by the stern, and 2° by the stern, to understand the difference between their seakeeping performances. The results in this study provide a useful guideline for evaluating operational regulations and safety for high speed semi-planing crafts in the future.

SUPERIOR SEAWORTHINESS OF A RESONANCE-FREE FAST OCEANGOING SWATH

2021 ◽  
Vol 156 (A4) ◽  
Author(s):  
M Yoshida ◽  
H Kihara ◽  
H Iwashita ◽  
M Kanda ◽  
T Kinoshita
Keyword(s):  
High Speed ◽  
Time Lag ◽  
Ship Motions ◽  
Speed Reduction ◽  
Small Water ◽  
Motion Responses ◽  
Head Waves ◽  
Unsteady Characteristics ◽  
Hull Forms ◽  
Heave Motion

The speed reduction, additional resistance or slamming caused by the large amplitude ship motions, should be completely restricted for a large fast oceangoing ship because of the strict time-punctuality and the high value of the cargo. A “Resonance-Free SWATH (RFS)”, which has negative restoring moments due to the extremely small water plane area, is introduced to minimize the motion responses. A motion control system using small fins is necessary for the RFS, which has no stability during high speed cruising. Theoretical estimations and experiments to search for the optimum values of PD control gains have been performed. Unsteady characteristics of fin-generated lift such as the time lag and the interaction among the fins and lower hulls have been measured and they are taken into account in the motion equations. Then, experiments using the RFS model with controlling fins have been carried out to validate the theoretical estimation for the motion responses of the RFS in waves. The theoretical and experimental results agree well with each other. The motion responses of the RFS in regular and irregular head waves are compared with those of other hull forms, such as a mono-hull, an ordinary SWATH and a trimaran. The clear advantage of the RFS regarding the seaworthiness has been found. In summary, the heave motion response of the RFS is reduced to 1/60 and the pitch motion becomes1/8, compared with those of the existing mono-hull ship.

Experimental Investigation on Element Immersing Process of Immersed Tube Tunnel of Hong Kong-Zhuhai-Macao Bridge

2012 ◽  
Author(s):  
Sheng Peng ◽  
Weiguo Wu ◽  
Keqiang Chen ◽  
Aokui Xiong ◽  
Ziyu Xia
Keyword(s):  
Hong Kong ◽  
High Speed ◽  
Tunnel Construction ◽  
Ministry Of Education ◽  
Scaled Model ◽  
Current Test ◽  
System A ◽  
Sea Bed ◽  
Motion Responses ◽  
Immersed Tunnel

Hong Kong-Zhu hai-Macao Bridge, connecting world famous tri-cities in China, will consists of three different construction elements: a man made peninsula, a world’s longest and widest immersed tunnel and a cross-sea bridge. The key point of this megastructure is the construction of the immersed tube tunnel construction. The accuracy of tunnel element positioning directly determines the quality of tunnel construction. In order to study the behavior of elements during its lowering to the sea bed, the scaled model test has carried out in the Key Laboratory of High-speed Ship Engineering of Ministry of Education, Wuhan, China. Experiment was carried out to investigate the motion responses of the tunnel element in the immersion under wave and current actions and the tensions acting on the controlling cables of its immersing system. A concise description of the model wave-current test is carried out, and the variation of motion responses of the tunnel element and cable tensions against wave, current and immersing depth were obtained, which could be a guidance to the construction of the immersed tunnel of Hong Kong-Zhu hai-Macao Bridge.

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