Experimental Study of the Probability Distributions of Green Water on the Bow of Floating Production Platforms

2004 ◽  
Vol 127 (3) ◽  
pp. 234-242 ◽  
Author(s):  
C. Guedes Soares ◽  
R. Pascoal
Keyword(s):  
Experimental Study ◽  
Conditional Distribution ◽  
Probability Distributions ◽  
Green Water ◽  
Experimental Program ◽  
Separate Analysis ◽  
Response Process ◽  
Water On Deck ◽  
Distribution Water ◽  
Water Height

Results of an experimental program with a model of a moored floating production storage and offloading vessel are used to study the probability distributions associated with various phenomena related with green water loading. Separate analysis of wave height and crests are performed in order to assess the presence and significance of nonlinearities. Time series of pitch motion and relative motion are analyzed to check for linearity of the response process. Probability distributions of the occurrence of water on deck and of the conditional distribution water height above deck are also studied.

Experimental Study of the Probability Distributions of Green Water on the Bow of Floating Production Platforms

2002 ◽  
Author(s):  
Carlos Guedes Soares ◽  
Ricardo Pascoal
Keyword(s):  
Experimental Study ◽  
Conditional Distribution ◽  
Probability Distributions ◽  
Green Water ◽  
Experimental Program ◽  
Separate Analysis ◽  
Response Process ◽  
Water On Deck ◽  
Distribution Water ◽  
Water Height

Results of an experimental program with a model of a moored Floating Production Storage and Offloading (FPSO) vessel are used to study the probability distributions associated with various phenomena related with green water loading. Separate analysis of wave height and crests are performed in order to assess the presence and significance of nonlinearities. Time series of pitch motion and relative motion are analysed to check for linearity of the response process. Probability distributions of the occurrence of water on deck and of the conditional distribution water height above deck are also studied.

scholarly journals Experimental Study on the Torsional Behaviour of Prestressed HSC Hollow Beams

2020 ◽  
Vol 10 (2) ◽  
pp. 642 ◽  
Author(s):  
Luís Bernardo ◽  
Sérgio Lopes ◽  
Mafalda Teixeira
Keyword(s):  
Experimental Study ◽  
High Strength Concrete ◽  
Concrete Beams ◽  
Concrete Strength ◽  
High Strength ◽  
Experimental Program ◽  
Pure Torsion ◽  
Strength Concrete ◽  
Hollow Beams

This article describes an experimental program developed to study the influence of longitudinal prestress on the behaviour of high-strength concrete hollow beams under pure torsion. The pre-cracking, the post-cracking and the ultimate behaviour are analysed. Three tests were carried out on large hollow high-strength concrete beams with similar concrete strength. The variable studied was the level of longitudinal uniform prestress. Some important conclusions on different aspects of the beams’ behaviour are presented. These conclusions, considered important for the design of box bridges, include the influence of the level of prestress in the cracking and ultimate behaviour.

scholarly journals Experimental study of green water on rectangular structure with varying flare angle

2022 ◽  
Vol 243 ◽  
pp. 110252
Author(s):  
Gang Nam Lee ◽  
Kwang Hyo Jung ◽  
Seong Yun Shin ◽  
Hyun Jung Park ◽  
Sime Malenica ◽  
...  
Keyword(s):  
Experimental Study ◽  
Green Water

Experimental Study on the Influence of Hull Spacing on Hard-Chine Catamaran Motions

2001 ◽  
Vol 45 (03) ◽  
pp. 216-227
Author(s):  
R. Centeno ◽  
K. S. Varyani ◽  
C. Guedes Soares
Keyword(s):  
Experimental Study ◽  
Cross Flow ◽  
Experimental Program ◽  
Two Dimensional ◽  
Regular Waves ◽  
Viscous Forces ◽  
Motion Responses ◽  
Resonance Frequencies ◽  
Flow Drag ◽  
Wave Induced

An experimental program was performed with hard-chine catamaran models in regular waves. The distance between the demi-hulls of the models was changed to assess its effects on the wave-induced motions. The results allowed the study of some aspects related to catamaran motions, like the interference between the hulls and resonance frequencies. The experimental results are compared with calculations performed with a recently developed code based on a two-dimensional potential flow theory in which viscous forces are included through a cross-flow drag approach. The effect of the hull distance in the heave and pitch motion responses and the importance of the viscous forces in such hull configurations are shown.

scholarly journals Experimental study of water cooling effect on heat transfer to increase output power of 180 watt peak photovoltaic module

2018 ◽  
Vol 67 ◽  
pp. 01009
Author(s):  
Arrad Ghani Safitra ◽  
Fifi Hesty Sholihah ◽  
Erik Tridianto ◽  
Ikhsan Baihaqi ◽  
Ni Nyoman Ayu Indah T.
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Surface Temperature ◽  
Output Power ◽  
Cooling Water ◽  
Photovoltaic Module ◽  
Water Cooling ◽  
Water Replacement ◽  
Pv Modules ◽  
Water Height

Photovoltaic (PV) modules require solar radiation to generate electricity. This study aims to determine the effect of water cooling PV modules on heat transfer, output power, and electrical efficiency of PV modules. The experiments carried out in this study were to vary the heights of flooded water (with and without cooling water replacement control) and cooling water flow. Variations in the height of flooded water are 0,5 cm, 1 cm, 2 cm, and 4 cm. While the flow rate variations are 2 L/min, 4 L/min, and 8 L/min. The flooded water replacement control will be active when the PV surface temperature reached 45°C. When the temperature dropped to 35°C, the cooler is disabled to let more photon to reach PV surface. The results showed that the lowest heat transfer occurred in the variation of 4 cm flooded water height without water replacement control, i.e. 28.53 Watt, with an average PV surface temperature of 32.92°C. The highest average electric efficiency occurred in the variation of 0,5 cm flooded water height with water replacement control, i.e. 13.12%. The use of cooling water replacement control is better due to being able to skip more photons reach PV surface with low PV temperature.

Using a Simplified Smoothed Particle Hydrodynamics Model to Simulate Green Water on the Deck

2012 ◽  
Author(s):  
Csaba Pakozdi ◽  
Carl-Trygve Stansberg ◽  
Paal Skjetne ◽  
Wei Yang
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Diffraction Theory ◽  
Green Water ◽  
Test Time ◽  
Random Wave ◽  
Water On Deck ◽  
Simulation Speed ◽  
Slamming Load ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Severe storms have gained more attention in recent years. Improved metocean data have led to new insight into severe wave conditions for marine design. Therefore, there exists an industrial demand for fast and accurate numerical tools to estimate the hydrodynamic loads during e.g. green water events. Model tests generally play an important role in these studies. In the recent past, several practical engineering tools have also been developed, based on the experience from the experimental data bases in combination with simplified but still theoretical formulations. One such tool is Kinema2, which is based on non-linear random wave modeling combined with 3D linear diffraction theory to initially identify green water events, and then finally apply a simplified water-on-deck and slamming load estimation. This forms the background for the work presented in this paper which shows the feasibility of a new technique based on the Smoothed Particle Hydrodynamics (SPH). This method can give more detailed forecast of the hydrodynamics on the deck than the simplified water-on-deck estimation. SPH uses a Lagrangian framework (particles) to describe the fluid dynamics. The water propagation and kinematics of the green water events are, in this introductory stage of the study, reproduced by using a SPH inlet condition where particles are injected with given velocity from a curved rectangular area against the deck and the deckhouse. The relative wave height and water particle velocities found from KINEMA2. Numerical results for water elevation and velocity on deck are compared against model test time series and previous results from other numerical simulation methods. The present Lagrangian nature (compared to traditional Eulerian-VOF methods) can in principe significantly reduce the CPU demand and increase the simulation speed. Slamming pressures can then be calculated e.g. from simple slamming formula calculations. In principle, pressures can also be found directly from the SPH calculations, while this would demand a significantly larger number of particles which increases CPU demand of the SPH method.

scholarly journals Multiperiod conditional distribution functions for conditionally normal GARCH(1, 1) models

2005 ◽  
Vol 42 (02) ◽  
pp. 426-445
Author(s):  
Raymond Brummelhuis ◽  
Dominique Guégan
Keyword(s):  
Conditional Probability ◽  
Conditional Distribution ◽  
Probability Distributions ◽  
Random Variables ◽  
Distribution Functions ◽  
Tail Behavior ◽  
Asymptotic Tail

We study the asymptotic tail behavior of the conditional probability distributions of r t+k and r t+1+⋯+r t+k when (r t ) t∈ℕ is a GARCH(1, 1) process. As an application, we examine the relation between the extreme lower quantiles of these random variables.

Prediction of Green Water Events on FPSO Vessels

2003 ◽  
Author(s):  
Alexander Fyfe ◽  
Edward Ballard
Keyword(s):  
Probability Distributions ◽  
Green Water ◽  
Design Stage ◽  
Wave Crest ◽  
Peak Period ◽  
Wave Conditions ◽  
Motion Characteristics ◽  
Central North Sea

Most floating vessels experience some sea states, not necessarily extreme storms, which cause large volumes of green water to flow across the deck. Due to the location of safety critical equipment on the deck of FPSOs, the determination of the likely occurrences and the magnitudes of such events are critical to safe design and operation. A method for the determination of green water heights on the deck of an FPSO has been presented in references 1–5. This paper examines the long-term distributions of heights implied by these references and the identification of sea states in which extreme events are likely to occur. The method is based upon the long term distribution of sea states at the intended location, combined with the motion characteristics of the vessel. Freeboard exceedance at the bow and at a point along the side is considered for two typical FPSO configurations. The methodology presented is widely applicable to many locations but wave conditions typical of the Central North Sea are used by way of illustration. The results presented include long term probability distributions of green water height on deck at locations of interest. Relative contributions of each combination of significant wave height and peak period to the probability of the largest single event in a defined return period are determined and discussed. It is shown that the wave conditions most likely to give rise to the most severe green water events are seldom those characterized by the largest wave crest heights. Instead, there exists a complex dependence on characteristic periods associated with vessel motions and on the long-term occurrences of particular sea states. The ability to predict conditions in which the largest green water events are most likely to occur offers the possibility of providing improved operational guidelines for FPSOs, allowing action to be taken to avoid unfavourable loading conditions and/or vessel headings in certain sea conditions. However, it is also shown that it may be difficult to identify some severe green water sea states from normally available forecast data and hence it is important that appropriate provision is made at the design stage.

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