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- Energetic functional (1)
- Energetic temporal boundary functions (1)
- Fast Fourier transforms (FFT) (1)
- Hydro-meteorology (1)
- Inverse nonlinear oscillator problem (1)
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- Iterative method (1)
- Jacket-type (1)
- Model test (1)
- Monopile (1)
- Multiship encounter (1)
- Nomoto?€(TM)s second-order model (1)
- Offshore wind turbine (1)
- Phase shift (1)
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- Sea ice (1)
- Sea trial (1)
- Shallow water area (1)
- Spectral analysis (1)
- The maximum scour depth (1)
- Water waves (1)
Articles 1 - 5 of 5
Full-Text Articles in Mechanical Engineering
Fft Phase Shift Of Water Wave Analysis, Chu-Kuan Lin, Shih-Yu Hsu, Jaw-Guei Lin
Fft Phase Shift Of Water Wave Analysis, Chu-Kuan Lin, Shih-Yu Hsu, Jaw-Guei Lin
Journal of Marine Science and Technology
The fast Fourier transform (FFT) has been accepted as a tool for signal processing. This study conducted a series of numerical experiments using Matlab. By conducting FFT analysis on designated wave trains, the FFT results revealed that an extra phase shift of ��ሺ2�� ��⁄ ሻ , with N representing the number of data points for an i-th wave component, was implicitly added to the analyzed phases during the analysis. When extra phase shifts were subtracted from the analyzed phases of each component, signals could be completely reconstructed in the time domain with an acceptable difference. This study tested component and …
Protective Effect Of An Ice-Breaking Structure On Offshore Structures In Shallow Waters, Ji-Wu Dong, Zhi-Jun Li, Xiang-Peng Kong, Xiao-Dong Liang
Protective Effect Of An Ice-Breaking Structure On Offshore Structures In Shallow Waters, Ji-Wu Dong, Zhi-Jun Li, Xiang-Peng Kong, Xiao-Dong Liang
Journal of Marine Science and Technology
In this study, an ice-breaking structure (IBS) was designed to break large ice floes into small fragments through flexural failure predominantly for protecting offshore structures in shallow waters. The protective effect of the IBS on a vertical isolated cylindrical pile (ICP), which was examined through the model tests of the crushing ice loads and collision forces on the ICP from ice pieces broken with the IBS under identical conditions, was evaluated by obtaining the relative difference between the maximum values of the horizontal crushing forces and collision loads on the ICP. The results indicated a notable protective effect of the …
Identifying Nonlinear Oscillators By An Energetic Functional In The Linear Space Of Temporal Boundary Functions, Chein-Shan Liu, Yung-Wei Chen, Jiang-Ren Chang
Identifying Nonlinear Oscillators By An Energetic Functional In The Linear Space Of Temporal Boundary Functions, Chein-Shan Liu, Yung-Wei Chen, Jiang-Ren Chang
Journal of Marine Science and Technology
We resolve the inverse problems of a second-order nonlinear oscillator to recover time-dependent damping function and nonlinear restoring force, with the help of temporal boundary data measured at initial time and final time. By using these data, a sequence of temporal boundary functions of time is derived, which satisfy the measured temporal boundary conditions automatically, and are at least the fourth-order polynomials of time. All the temporal boundary functions and zero element constitute a linear space, and a new concept of energetic functional is introduced in the linear space, of which the energy is preserved for each energetic temporal boundary …
The Effect Of Hydro-Meteorology On Ship Collision Avoidance In Heavy Traffic Areas With A Simplified Simulation Model, Ming-Chung Fang, Kun-Yuan Tsai, Chih-Chung Fang
The Effect Of Hydro-Meteorology On Ship Collision Avoidance In Heavy Traffic Areas With A Simplified Simulation Model, Ming-Chung Fang, Kun-Yuan Tsai, Chih-Chung Fang
Journal of Marine Science and Technology
On the basis of the ship collision avoidance steering system in calm water developed by the authors, this paper upgrades the numerical simulation model by considering various hydrometeorological factors for ships with nonuniform movement. A real-time simulator was used for the numerical simulation of the container ship. To clarify the validity of the maneuvering mathematical model, sea trial results for the container ship were compared with the results for the present simulation system in terms of turn trajectory. In this study, a numerical technique based on Nomoto’s second-order model was employed to investigate the turning characteristics of a container ship. …
Experimental Study Of Scour Around Monopile And Jacket-Type Offshore Wind Turbine Foundations, Hsin-Hung Chen
Experimental Study Of Scour Around Monopile And Jacket-Type Offshore Wind Turbine Foundations, Hsin-Hung Chen
Journal of Marine Science and Technology
Wind turbines platforms and pillars on offshore wind farms are negatively affected by wave and current action. In Taiwan, the water depth of most planned wind turbine foundations is more than 15 m. At this water depth, scour around offshore wind turbine foundations is mainly subject to the ocean current, which causes damage or collapse of foundations. Therefore, this study focused on the influence of ocean current on the monopile and jacket-type foundations of offshore wind turbines. Hydraulic model experiments were conducted to investigate the maximum scour depth and range around pillars in these foundations. Under the effects of current, …