scholarly journals STABILITY OF RUBBLE MOUND SLOPES UNDER RANDOM WAVE ATTACK

1984 ◽  
Vol 1 (19) ◽  
pp. 176 ◽  
Author(s):  
J.W. Van der Meer ◽  
K.W. Pilarczyk
Keyword(s):  
Model Tests ◽  
Wave Period ◽  
Present Series ◽  
Random Wave ◽  
Research Project ◽  
Spectrum Shape ◽  
The Core ◽  
Practical Design ◽  
Relevant Variables ◽  
Rubble Mound

The objective of the present research project is to give new practical design formulae for rubble mound slopes under random wave attack. The study is based upon a series of model tests. More than two hundred tests have been performed in order to vary systematically all the relevant variables. The main shortcomings in Hudson-type formulae have been solved as a result of the present series of investigations. Stability formulae are given which include the influence of wave period, number of waves, armour grading, spectrum shape, groupiness of waves and the permeability of the core.

scholarly journals WAVE OVERTOPPING ON RUBBLE MOUND BREAKWATERS

1988 ◽  
Vol 1 (21) ◽  
pp. 57 ◽  
Author(s):  
Pierliugi Aminti ◽  
Leopoldo Franco
Keyword(s):  
Hydraulic Model ◽  
Model Tests ◽  
Geometric Parameters ◽  
Random Wave ◽  
Wave Overtopping ◽  
Wave Flume ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

The paper gives the results of an extensive series of hydraulic model tests carried out in a random wave flume, in order to study the effects on wave overtopping of the main geometric parameters of a typical rubble mound breakwater with crown wall. The results have been compared with those from other studies and analyzed with different methods. Generalized design diagrams and formulae for the prediction of overtopping discharges are finally given for a large number of popular breakwater configurations.

scholarly journals WAVE OVERTOPPING AT BERM BREAKWATERS IN LINE WITH EUROTOP

2012 ◽  
Vol 1 (33) ◽  
pp. 12 ◽  
Author(s):  
Sigurdur Sigurdarson ◽  
Jentsje W. Van der Meer
Keyword(s):  
Hydraulic Model ◽  
Model Tests ◽  
Wave Period ◽  
Wave Steepness ◽  
Wave Overtopping ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

The paper presents the development of a new overtopping formula for berm breakwaters. Overtopping data from hydraulic model tests of berm breakwaters have been gathered and reanalysed in line with the procedure in the EurOtop Manual. The data shows a clear dependency on wave period or wave steepness, which is in contrast to the main conclusion of the CLASH project and the EurOtop Manual for conventional rubble mound breakwaters. The formula is roughly validated on prototype performance.

Study on vertical motion reduction of a trimaran based on collaborative controlled appendages

2020 ◽  
Vol 17 (6) ◽  
pp. 172988142097677
Author(s):  
Zhilin Liu ◽  
Linhe Zheng ◽  
Guosheng Li ◽  
Shouzheng Yuan ◽  
Songbai Yang
Keyword(s):  
Experimental Study ◽  
Vertical Motion ◽  
Model Tests ◽  
Wave Period ◽  
Regular Waves ◽  
Towing Tank ◽  
Vertical Stability ◽  
Stabilization Control ◽  
Stability Performance

In recent years, the trimaran as a novel ship has been greatly developed. The subsequent large vertical motion needs to be studied and resolved. In this article, an experimental study for a trimaran vertical stabilization control is carried out. Three modes including the bare trimaran (the trimaran without appendages, the trimaran with fixed appendages, and the trimaran with controlled appendages) are performed through model tests in a towing tank. The model tests are performed in regular waves. The range of wave period is 2.0–4.0 s, and the speed of the carriage is 2.93 and 6.51 m/s. The results of the three modes show the fixed appendages and the actively controlled appendages are all effective for the vertical motion reduction of the trimaran. Moreover, the controlled appendages are more effective for the vertical stability performance of the trimaran.

The Mooring Bay Concept for LNG Loading in Harsh and Ice Conditions

2012 ◽  
Author(s):  
Sven Hoog ◽  
Joachim Berger ◽  
Johannes Myland ◽  
Günther F. Clauss ◽  
Daniel Testa ◽  
...  
Keyword(s):  
Natural Gas ◽  
Model Tests ◽  
The Arctic ◽  
Transfer System ◽  
Research Project ◽  
Joint Research ◽  
Gas Treatment ◽  
Ice Coverage ◽  
Joint Research Project ◽  
Flexible Transfer Lines

The demand for natural gas from offshore fields is continuously increasing. Especially future production from Arctic waters comes into focus in context with global warming effects leading to the development of a dedicated technology. Relevant approaches work with floating turret moored production terminals (FLNG) receiving gas via flexible risers from subsea or onshore fields. These terminals provide on-board gas treatment and liquefaction facilities as well as huge storage capabilities for LNG (Liquefied Natural Gas), LPG (Liquefied Petrol Gases) and condensate. Products are transferred to periodically operating shuttle tankers for onshore supply reducing the need for local onshore processing plants providing increased production flexibility (future movability or adaptation of capacity). Nevertheless, in case of harsh environmental conditions or ice coverage the offshore transfer of cryogenic liquids between the terminal and the tankers becomes a major challenge. In the framework of the joint research project MPLS20 ([1]), an innovative offshore mooring and cargo transfer system has been developed and analyzed. MPLS20 is developed by the project partners Nexans ([2]) and Brugg ([3]), leading manufacturers of vacuum insulated, flexible cryogenic transfer pipes, IMPaC ([4]), an innovative engineering company that has been involved in many projects for the international oil and gas industry for more than 25 years and the Technical University (TU) Berlin, Department of Land- and Sea Transportation Systems (NAOE, [5]), with great expertise in numerical analyses and model tests. The overall system is based on IMPaC’s patented and certified offshore ‘Mooring Bay’ concept allowing mooring of the vessels in tandem configuration and simultaneous handling and operation of up to six flexible transfer pipes in full aerial mode. The concept is outlined to operate with flexible transfer lines with 16-inch inner diameter like the newly designed and certified corrugated pipes from Nexans and Brugg. The mooring concept and its major subsystems have proven their operability by means of extensive numerical analysis, model tests and a professional ship handling simulator resulting in an overall transfer solution suitable to be used especially under Arctic conditions like addressed by the EU joint research project ACCESS (http://access-eu.org/). The paper introduces the new offshore LNG transfer system and focuses especially on its safe and reliable operability in the Arctic — with ice coverage as well as in open water conditions.

scholarly journals Practical Precision Electrical Impedance Measurement for the 21st Century – EMPIR Project 17RPT04 VersICal

2019 ◽  
Author(s):  
Oliver Power ◽  
Adam Ziolek ◽  
Andreas Elmholdt Christensen ◽  
Andrei Pokatilov ◽  
Anca Nestor ◽  
...  
Keyword(s):  
21St Century ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
Research Project ◽  
The Core ◽  
First Results ◽  
Electrical Impedance Measurement ◽  
Measurement Infrastructure

The core objective of EMPIR project 17RPT04 VersICaL is to improve the European measurement infrastructure for electrical impedance, with particular emphasis on the capabilities of developing NMIs and calibration centres. The project will seek to exploit the results of existing research on digital impedance bridges (DIBs) by designing, constructing and validating simple, affordable versions suitable to realise the impedance scale in the range 1 nF to 10 μF and 1 mH to 10 H with relative uncertainties in the range 10-5 to 10-6. The first results of the research project, including the bridge designs and details of a polyphase digitally synthesized multichannel source capable of providing voltage outputs of precise ratio and phase are presented.

scholarly journals Correction: Eldrup, M.R., et al. Stability of Rubble Mound Breakwaters—A Study of the Notional Permeability Factor, based on Physical Model Tests. Water 2019, 11, 934

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2483
Author(s):  
Mads Røge Eldrup ◽  
Thomas Lykke Andersen ◽  
Hans Falk Burcharth
Keyword(s):  
Physical Model ◽  
Model Tests ◽  
Permeability Factor ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

The authors wish to make the following corrections to this paper [...]

scholarly journals Creativity in events: the untold story

2018 ◽  
Vol 9 (1) ◽  
pp. 2-19 ◽  
Author(s):  
Caroline Jackson ◽  
James Morgan ◽  
Chantal Laws
Keyword(s):  
Design Methodology ◽  
Theoretical Framework ◽  
Creative Industries ◽  
Creative Economy ◽  
Event Management ◽  
Research Project ◽  
Content Type ◽  
The Core ◽  
Creative Environment

Purpose The purpose of this paper is to report on untold stories that not only illustrate the creativity but also complexity of working in outdoor events. There has been global interest in the creative industries and the creative economy more generally. Events have not been identified or categorised as part of this. Experiences have been identified as part of the creative sectors (NESTA, 2006) and events are seen as experiences (Jackson, 2006; Berridge 2007). There has been little research undertaken about the creative nature of event experiences, especially in how they are created. Design/methodology/approach A theoretical framework was created from literature on creativity more generally to inform the Creativity in Events research project. Interviews with those working in the outdoor events sector were the basis of the qualitative stage of the research project investigating the phenomenon of creativity in events. Findings This paper identifies the core facets of creativity in the management of outdoor events. These were fluency, originality, imagination, elaboration, environment and complexity. A vignette is used to illustrate the intricacy of the nature of creativity in the production of outdoor event experiences. The overall findings were that event management was both creative and pragmatic and that both are necessary. There was a need for a creative environment with processes and familiarity that aided inspiration and originality. Originality/value The background and findings are relevant to recognising events as part of the wider creative economy. A greater understanding of the nature of creativity in events informs both education and practice.

Green Sea and Water Impact on FPSO: Numerical Predictions Validated Against Model Tests

2002 ◽  
Author(s):  
C. T. Stansberg ◽  
O̸. Hellan ◽  
J. R. Hoff ◽  
V. Moe
Keyword(s):  
Structural Integrity ◽  
Design Method ◽  
Model Tests ◽  
Random Wave ◽  
Simplified Approach ◽  
Irregular Wave ◽  
Wave Kinematics ◽  
Numerical Predictions ◽  
Statistical Sense ◽  
Local Pressures

A recently developed numerical design method for analysis of green sea events and resulting impact loads on deck structures of FPSO’s, is validated against model test data. Steep irregular wave conditions are considered, and numerical time series reconstructions are made using the measured wave as input. A second-order numerical random wave description is combined with standard 3D wave diffraction and related vessel motions to predict the relative wave kinematics. A modified shallow water formulation is applied for the prediction of the propagation on deck, and resulting local pressures on the deck-house are estimated by a similarity solution. From this an analysis of the structural integrity can be made. Comparisons to the experiments are made for the relative wave amplitudes, water propagation on deck, and the resulting deck-house loads. A reasonably good agreement is observed for the reconstructions, in a statistical sense, but also for individual events. Thus selected green sea events are investigated in detail, and characteristics identified. The agreement with the model tests is promising especially on the background of the simplified approach used, as well as the expected statistical scatter.

scholarly journals STATISTICAL PROPERTIES OF RANDOM WAVE GROUPS

1980 ◽  
Vol 1 (17) ◽  
pp. 175 ◽  
Author(s):  
Akira Kimura
Keyword(s):  
Wave Height ◽  
Transition Probabilities ◽  
Probability Distributions ◽  
Group Formation ◽  
Rayleigh Distribution ◽  
Statistical Properties ◽  
Wave Period ◽  
Random Wave ◽  
Random Waves ◽  
Resonant Wave

This study deals with the statistical properties of the group formation of random waves determined by the zero-up-cross method. Probability distributions about (1) the run of high waves (2) the total run (3) the run of resonant wave period are derived theoretically providing that the time series of wave height and wave period form the Markov chain. Transition probabilities are given by the 2-dimensional Rayleigh distribution for the wave height train and the 2-dimensional Weibull distribution for the wave period train. And very good agreements between data and the theoretical distributions have been obtained. Then the paper discusses those parameters which affect the statistical properties of the runs and shows that the spectrum peakedness parameter for the. run of wave height and the spectrum width parameter for the run of wave period are the most predominant.

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