A Systematic Study on Berthing Capacity Assessment of Sanya Yazhou Fishing Port by Typhoon Prediction Model

This paper sheds light on the effect of combination modes on the evaluation of berthing capacity for Sanya Yazhou Fishing Port (SYFP) under hypothetical typhoon conditions. By statistically analysing the maximum probability of moving speeds and directions of historical typhoons passing through the fishing port, the representative typhoon path was determined with the nonparametric regression method. The designed typhoon wind fields of levels 12–17 were generated based on Holland’s parametric wind model. Then, the MIKE 21 BW model was used to obtain the high-precision wave distribution in the fishing port. The boundary conditions (significant wave height and peak period) of the MIKE 21 BW model were calculated by combining the MIKE 21 SW model with the designed typhoon wind fields. In SYFP, ships usually adopt the modes of multi-ship side-by-side and single anchor mooring during typhoons. In fair weather, approximately 158 vessels can be berthed if they are all large ones, while approximately 735 vessels can be moored if they are all small ones. However, with an increase in typhoon levels, the anchoring area for small vessels decreases. From the perspective of wave distribution in the fishing port, the number of large vessels moored was hardly affected by typhoons. This can be attributed to the breakwater, which significantly decreases the large wave height in the fishing port. Finally, a study on the framework of a method for hazard assessment of berthing capacity in the coming typhoon-driven storm waves was set up.

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ASSESSMENT OF LONG-TERM WIND AND WAVE TRENDS IN THE BLACK SEA

Coastal Engineering Proceedings ◽

10.9753/icce.v36v.waves.5 ◽

2020 ◽

pp. 5

Author(s):

Fulya Islek ◽

Yalcin Yuksel ◽

Cihan Sahin

Keyword(s):

Climate Change ◽

Black Sea ◽

Wave Climate ◽

The Black Sea ◽

Wind Fields ◽

Wave Characteristics ◽

Wind Characteristics ◽

Mike 21 Sw ◽

Mike 21

The wind and wave climate over the Black Sea were investigated by providing extensive datasets covering the last 40 years (1979-2018). Wind characteristics over the Black Sea were evaluated by using two well-known wind fields (i.e., ECMWF ERA-Interim and NCEP/CFSR). Wave simulations were generated from the MIKE 21 SW model forcing with two wind datasets. The possible effect of the long-term variability on the wind and wave characteristics over the Black Sea was discussed in the context of climate change.

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Non-stationary extreme value analysis of sea states based on linear trends. Analysis of annual maxima series of significant wave height and peak period in the Mediterannean Sea

Coastal Engineering ◽

10.1016/j.coastaleng.2021.103896 ◽

2021 ◽

pp. 103896

Author(s):

Francesco De Leo ◽

Giovanni Besio ◽

Riccardo Briganti ◽

Erik Vanem

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Extreme Value ◽

Extreme Value Analysis ◽

Peak Period ◽

Value Analysis ◽

Significant Wave ◽

Trends Analysis ◽

Linear Trends

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Semi-Empirical Crest Distributions of Long-Crest Nonlinear Waves of Three-Hour Duration

Volume 1: Offshore Technology ◽

10.1115/omae2017-61226 ◽

2017 ◽

Author(s):

Zhenjia (Jerry) Huang ◽

Qiuchen Guo

Keyword(s):

Nonlinear Wave ◽

Wave Height ◽

Model Test ◽

Significant Wave Height ◽

Spectral Peak ◽

Wave Crest ◽

Empirical Formulas ◽

Peak Period ◽

Significant Wave ◽

Semi Empirical

In wave basin model test of an offshore structure, waves that represent the given sea states have to be generated, qualified and accepted for the model test. For seakeeping and stationkeeping model tests, we normally accept waves in wave calibration tests if the significant wave height, spectral peak period and spectrum match the specified target values. However, for model tests where the responses depend highly on the local wave motions (wave elevation and kinematics) such as wave impact, green water impact on deck and air gap tests, additional qualification checks may be required. For instance, we may need to check wave crest probability distributions to avoid unrealistic wave crest in the test. To date, acceptance criteria of wave crest distribution calibration tests of large and steep waves of three-hour duration (full scale) have not been established. The purpose of the work presented in the paper is to provide a semi-empirical nonlinear wave crest distribution of three-hour duration for practical use, i.e. as an acceptance criterion for wave calibration tests. The semi-empirical formulas proposed in this paper were developed through regression analysis of a large number of fully nonlinear wave crest distributions. Wave time series from potential flow simulations, computational fluid dynamics (CFD) simulations and model test results were used to establish the probability distribution. The wave simulations were performed for three-hour duration assuming that they were long-crested. The sea states are assumed to be represented by JONSWAP spectrum, where a wide range of significant wave height, peak period, spectral peak parameter, and water depth were considered. Coefficients of the proposed semi-empirical formulas, comparisons among crest distributions from wave calibration tests, numerical simulations and the semi-empirical formulas are presented in this paper.

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THE INFLUENCE OF CENTRE BOW LENGTH ON SLAMMING LOADS AND MOTIONS OF LARGE WAVE-PIERCING CATAMARANS

The International Journal of Maritime Engineering ◽

10.5750/ijme.v160ia1.1047 ◽

2021 ◽

Vol 160 (A1) ◽

Author(s):

J R Shahraki ◽

G A Thomas ◽

M R Davis

Keyword(s):

Wave Height ◽

Full Scale ◽

Bending Moments ◽

Regular Waves ◽

Large Wave ◽

Towing Tank ◽

Segmented Model ◽

Model Experiments ◽

Slamming Load ◽

Wave Induced

The effect of various centre bow lengths on the motions and wave-induced slamming loads on wave-piercing catamarans is investigated. A 2.5 m hydroelastic segmented model was tested with three different centre bow lengths and towed in regular waves in a towing tank. Measurements were made of the model motions, slam loads and vertical bending moments in the model demi-hulls. The model experiments were carried out for a test condition equivalent to a wave height of 2.68 m and a speed of 20 knots at full scale. Bow accelerations and vertical bending moments due to slamming showed significant changes with the change in centre bow, the longest centre bow having the highest wave-induced loads and accelerations. The increased volume of displaced water which is constrained beneath the bow archways is identified as the reason for this increase in the slamming load. In contrast it was found that the length of centre bow has a relatively small effect on the heave and pitch motions in slamming conditions.

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Development of Operational Limit Diagrams for Offshore Lifting Procedures

Volume 1: Offshore Technology; Offshore Geotechnics ◽

10.1115/omae2015-42270 ◽

2015 ◽

Author(s):

Leonardo Roncetti ◽

Fabrício Nogueira Corrêa ◽

Carl Horst Albrecht ◽

Breno Pinheiro Jacob

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Technological Development ◽

Automatic Generation ◽

Dynamic Responses ◽

Offshore Platforms ◽

Peak Period ◽

Significant Wave ◽

Wave Heights ◽

Offshore Crane

Lifting operations with offshore cranes are fundamental for proper functioning of a platform. Despite the great technological development, offshore cranes load charts only consider the significant wave height as parameter of environmental load, neglecting wave period, which may lead to unsafe or overestimated lifting operations. This paper aims to develop a method to design offshore crane operational limit diagrams for lifting of personnel and usual loads, in function of significant wave height and wave peak period, using time domain dynamic analysis, for a crane installed on a floating unit. The lifting of personnel with crane to transfer between a floating unit and a support vessel is a very used option in offshore operations, and this is in many cases, the only alternative beyond the helicopter. Due to recent fatal accidents with lifting operations in offshore platforms, it is essential the study about this subject, contributing to the increase of safety. The sea states for analysis were chosen covering usual significant wave heights and peak periods limits for lifting operations. The methodology used the SITUA / Prosim software to obtain the dynamic responses of the personnel transfer basket lifting and container loads on a typical FPSO. Through program developed by the author, it was implemented the automatic generation of diagrams as a function of operational limits. It is concluded that using this methodology, it is possible to achieve greater efficiency in the design and execution of personnel and routine load lifting, increasing safety and a wider weather window available.

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Comparison of Bivariate Models of the Distribution of Significant Wave Height and Peak Wave Period

Volume 2: Structures, Safety and Reliability; Petroleum Technology Symposium ◽

10.1115/omae2007-29740 ◽

2007 ◽

Cited By ~ 4

Author(s):

Catarina S. Soares ◽

C. Guedes Soares

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Bivariate Normal Distribution ◽

Wave Period ◽

Peak Period ◽

Data Set ◽

Significant Wave ◽

The North ◽

Bivariate Models ◽

The North Sea

This paper presents the results of a comparison of the fit of three bivariate models to a set of 14 years of significant wave height and peak wave period data from the North Sea. One of the methods defines the joint distribution from a marginal distribution of significant wave height and a set of distributions of peak period conditional on significant wave height. Other method applies the Plackett model to the data and the third one applies the Box-Cox transformation to the data in order to make it approximately normal and then fits a bivariate normal distribution to the transformed data set. It is shown that all methods provide a good fit but each one have its own strengths and weaknesses, being the choice dependent on the data available and applications in mind.

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Spectral Analysis of Irregular Wave Impact on the Structure in Splash Zone

21st International Conference on Offshore Mechanics and Arctic Engineering, Volume 1 ◽

10.1115/omae2002-28091 ◽

2002 ◽

Cited By ~ 1

Author(s):

Bing Ren ◽

Yongxue Wang

Keyword(s):

Spectral Analysis ◽

Wave Height ◽

Incident Wave ◽

Impact Pressure ◽

Splash Zone ◽

Spectral Moment ◽

Wave Impact ◽

Large Wave ◽

Irregular Wave ◽

The Impact

The spectral analysis from experimental data of irregular wave impact on the structures with large dimension in the splash zone is presented. The experiments were conducted in the large wave-current tank in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. In the experiment, the target spectrum is JONSWAP spectrum, the significant wave height H1/3 is in the range from 0.1m to 0.3m, and the peak period of spectrum Tp in the range from 1.0s to 2.0s. The ratio of s/H1/3, which refers to the clearance of the subface of the structure above still water level (s) to the incident wave height, is between −0.1 and 0.4. The spectral analysis results of the irregular wave impact pressure on the subface of the structure under various case studies are presented. The distribution of spectral moment of the impact pressure on the structure along the subface is given. And the influence of different incident wave parameters and relative clearance s/H1/3 on the average spectral moment of impact pressure are discussed.

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Spectral Modeling of Sea States With Multiple Wave Systems

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.2919981 ◽

1992 ◽

Vol 114 (4) ◽

pp. 278-284 ◽

Cited By ~ 47

Author(s):

C. Guedes Soares ◽

M. C. Nolasco

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Theoretical Models ◽

Wave System ◽

Spectral Parameters ◽

Peak Period ◽

Multiple Wave ◽

Significant Wave ◽

General Acceptance ◽

Spectral Models

The spectral models of individual wave systems have one peak and are described by theoretical models that have gained general acceptance. This work deals with sea states with more than one wave system, leading to spectral models with two or more peaks. Use is made of spectra derived from measurements off the Portuguese Coast and data is provided as to their probability of occurrence as well as about the dependence of the spectral parameters on the significant wave height and peak period. It is shown that wind-dominated and swell-dominated two-peaked spectra tend to occur in different areas of the scatter diagram. The spectral parameters of the two-peaked spectra show little correlation with significant wave height and peak period.

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