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Journal ArticleDOI

Experimental investigation of extreme wave impacts on a rigid TLP model in cyclonic conditions

17 Feb 2017-Ships and Offshore Structures (Taylor & Francis)-Vol. 12, Iss: 2, pp 153-170

AbstractThis paper describes a series of model tests of a rigidly mounted tension leg platform (TLP) subjected to extreme wave events corresponding to long-crested irregular wave trains of a 10,000-year cyclonic sea state. The experimental setup was instrumented to simultaneously measure wave surface elevations in the vicinity of the model, global wave impact forces and local pressure distribution on the underside of the model's topside deck. Model accelerations were also monitored for each wave impact event so that the inertial force due to structural dynamic response could be identified. The deck–column intersection areas were found to experience large wave-in-deck slamming pressures, in particular around the aft columns. A reduction of the deck clearance was found to increase the magnitude of the global horizontal forces; however, the global vertical forces and local wave-in-deck slamming pressures did not follow this trend.

Topics: Slamming (59%), Sea state (53%)

Summary (3 min read)

Introduction

  • Loads generated by extreme wave-in-deck events are one of the most important causes of damage to fixed and floating offshore structures, especially in extreme storm conditions (Kaiser et al., 2009, Abdussamie et al., 2014a, Forristall, 2007, Scharnke and Hennig, 2015, Buchan et al., 1999, REUTERS, 2016).
  • Another example of this is the destruction of 126 offshore structures and the severe damage of 183 other structures during the period 2004 – 2005 due to the hurricanes Ivan, Katrina and Rita in the Gulf of Mexico (Kaiser et al., 2009).
  • The overset grid technique was used to model rigid body motions.

Experimental setup

  • The TLP model was divided into two parts namely a hull module (columns and pontoons) and a topside deck module.
  • Wave elevation measured by WP3 over four repeated runs and the resulting surge motion measured by the MLDT are shown in Figure 5, whilst the simultaneous wave elevations measured at the topside deck LE (WP4) and TE (WP5) are plotted in Figure 6.
  • It is worth mentioning that the down-wave tendons were found to be susceptible to slack situations (≈ zero tension) caused by a large suction force as evident from the trough amplitude (-) measured at WP5 (TE) which was found to be larger than that measured at WP4 (LE), see Table 6.
  • The maximum and minimum values, the first quartile (the 25th percentile) and third quartile (the 75th percentile), Q1 and Q3, as well as the median pressure values, measured in multiple runs were combined into a single plot.
  • Such a finding highlights that the magnitude of slam pressure is very variable and its variability seems to be affected by the transducer location: whether near side edges, around the columns or in the middle of the deck underside.

Numerical investigation

  • The commercial Navier-Stokes CFD code STAR-CCM+ (Release 10) developed by CDadapco was used for simulating the physics of the wave-in-deck problem.
  • The VOF model implemented in STAR-CCM+ was used for capturing the interface between two immiscible fluids, herein water and air phases.
  • The method proposed by Choi and Yoon (2009) is implemented into STAR-CCM+ for damping the vertical motion of the free surface.
  • When generating the overset mesh, particular attention should be given to 1.
  • In order to model the desired wave characteristics, an incoming wave with appropriate height and wave period was specified at the inflow domain boundary (x = 0.0) shown on the left side of the diagram presented in Figure 12.

Solution settings

  • The following solution parameters were found to be important to achieve good wave impact simulations: time step and the effect of damping zone (wave reflection).
  • Pure HRIC scheme is used when the local Courant number is below the lower limit (0.5), whereas a pure first-order upwind scheme is automatically activated for Courant number higher than the upper limit (1.0).
  • The second-order discretisation of unsteady terms in momentum equations and HRIC scheme for the solution of the volume fraction equations was adopted in all simulations.
  • In order to capture slam pressure distribution at the deck underside, different levels of mesh refinement were investigated as summarised in Table 12.
  • Fine surface mesh was applied to the entire underside of the topside deck .

Wave quality

  • The accuracy of the CFD wave elevations was assessed on the basis of the input wave height.
  • It is worth mentioning that wave period computed were found to be exactly same of the input one.
  • As the wave propagates along the domain, similar to model tests, its crest height decays thereby underestimating the input wave height.
  • In addition, the wave elevation along the domain at volume fraction of water = 0.5 was obtained at different instances of time .
  • It should be noted that it is difficult to simulate waves with zero transport losses numerically due to relaxed spatial and temporal discretisation (Abdussamie et al., 2014b, Saripilli et al., 2014).

Mesh density

  • The maximum wave-in-deck slam pressure caused by the steepest wave condition (condition 5: Hinput = 201.6 mm, Tinput = 1.163 s) was utilised for sensitivity analyses due to local mesh density on the deck underside (Table 12).
  • By referring to Figure 18 and using the time history of a single wave period out of seven impact events, the effect of mesh density was noticeable when results of level 2 (fine mesh) and level 3 (finer mesh) were compared with those of level 1 (reference mesh).
  • These tests were conducted with air phase being incompressible and a time step of 0.001 s.
  • When level 1 was taken as the reference mesh level; there was an increase in the peak pressure (maximum pressure) of approximately 20% using level 2 and 47% using level 3 which indicates that finer mesh may be necessary.
  • The use of level 3 for local mesh refinement had an inconsistent effect on the maximum computed impact pressure indicating that the impact pressure is extremely localised phenomenon (Lee et al., 2014).

Air compressibility

  • The effect of air compressibility was tested by comparing results of the maximum wave-indeck pressure obtained using incompressible air phase with those performed using compressible air.
  • As seen in Figure 19, the air compressibility had an inconsistent effect on the slam pressure within the tested time frame.
  • The use of incompressible air rather resulted in a smoother pressure signal than that produced by a compressible fluid.

Comparison of experimental and CFD results

  • The first step was to conduct a numerical decay tests in STAR-CCM+ in order to obtain the damped natural periods of the combined TLP-mooring system.
  • Using still-water simulations, the model was initialised by prescribed values (initial translational or angular velocity of 0.3 m/s) along the DOF of interest and then released to move freely.
  • Table 13 summarises the results of these decay tests in the surge, heave and pitch degrees of freedom.
  • As an example, Figure 20 shows time traces of surge decay system and the corresponding FFT results.
  • Good agreement was achieved between the CFD and model tests, although damping ratios differed which can be attributed to the far-field boundary effects as the domain length was shorter than the physical tank.

Results of global response

  • Time histories of surge motion and tendon tensions for test conditions 2 and 3 are shown in Figure 21 and Figure 22, respectively.
  • The predicted surge motion and tendon tensions by CFD were found to be in good agreement with the experimental results.
  • Good agreement was achieved between the estimated and computed platform set-down for both conditions 2 and 3 indicating that the contribution of pitch motion in the magnitude of set-down was minimal.
  • Furthermore, the initial pretension used in CFD models was set as constant (To = 31.6 N).
  • As seen in Table 15, the measured leg pretension was found to be within 91% – 115% of the computed leg pretension.

Wave-in-deck impact events

  • During model experiments the wave-in-deck impact events were identified through pressure measurements and using high speed cameras.
  • 23 CFD models enabled for isolating the wave impact force components acting on the topside deck only (wave-in-deck forces) from the total hydrodynamic wave force being impacting on the TLP model.
  • The downward component of Fz which was found to be approximately synchronised with the minimum tendon tensions evidently caused such slack situations.
  • The pressure signal is denoted by four peaks (a) – (d).
  • The magnitude of impact pressure caused the first slam (a – b) was smaller but acting on larger area than that caused the second slam (c – d).

Conclusions

  • Experimental and CFD investigations of a moored tension leg platform (TLP) subjected to cyclonic regular wave conditions were conducted to examine the global response and wavein-deck impact problems.
  • The present numerical study using regular wave conditions validated against model tests could serve as a benchmark validation case for further numerical studies aimed at predicting wave-in-deck loading due to, e.g., combined waves with current and/or wind.
  • North Sea Storm Forces Oil Platform Evacuations, Output Shutdown [Online].
  • Proceedings of the ASME 33rd International Conference on Ocean, Offshore and Arctic Engineering, OMAE, 2014 San Francisco, CA, USA.

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1
Wave-in-deck loads and response of a TLP model in unidirectional regular
waves
Nagi Abdussamie
a
, Yuriy Drobyshevski
a
, Roberto Ojeda
a
, Giles Thomas
b
, Walid Amin
a
a
National Centre for Maritime Engineering and Hydrodynamics
Australian Maritime College, University of Tasmania, Launceston, TAS 7250, Australia
b
Department of Mechanical Engineering, University College London, UK
Abstract
Model tests of a moored tension leg platform (TLP) subjected to cyclonic conditions
represented by deterministic regular waves were conducted with the aim of validating state-
of-the-art two phase numerical simulations of wave-in-deck impact events. Tendon tension
forces and localised slamming pressures at the deck underside were simultaneously measured
using repeated runs. The computational fluid dynamics (CFD) simulations were based on the
volume of fluid (VOF) method implemented in the commercial CFD code STAR-CCM+.
The TLP’s rigid body motions and the effect of tendons were simulated by means of an
overset grid and massless spring lines, respectively. The global response and tendon tensions
computed by the CFD code were found to be in good agreement with the measurements. The
aft tendons were found to experience slackness following the deck impact in many wave
cycles. CFD results showed that the downward component of the vertical wave-in-deck force
was approximately synchronised with the minimum tendon tensions and evidently caused
such slack situations. Although CFD simulations indicated that there was a strong interaction
between water and air phases at the moment of impact, the air compressibility did not show a
significant difference on the magnitude of impact pressures.
Keywords: tension leg platforms; wave-in-deck loads; dynamic response; numerical
simulations.
Manuscript - with full author details Click here to download Manuscript - with full author details
Manuscript.pdf

2
Introduction
Loads generated by extreme wave-in-deck events are one of the most important causes of
damage to fixed and floating offshore structures, especially in extreme storm conditions
(Kaiser et al., 2009, Abdussamie et al., 2014a, Forristall, 2007, Scharnke and Hennig, 2015,
Buchan et al., 1999, REUTERS, 2016). Offshore installations such as those located in the
Australian North West Shelf (NWS), Gulf of Mexico and the North Sea are exposed to
cyclones/hurricanes which can generate these severe wave events. For instance, Buchan et al.
(1999) reported on the impact of tropical cyclone Olivia on Australia’s NWS. The storm
caused significant damage to oil and gas facilities in the region. Another example of this is
the destruction of 126 offshore structures and the severe damage of 183 other structures
during the period 2004 2005 due to the hurricanes Ivan, Katrina and Rita in the Gulf of
Mexico (Kaiser et al., 2009). Most recently, in December 2015, living quarters of 50 workers
of an offshore drilling rig in the North Sea were damaged when an enormous wave hit the
accommodation block and left one person dead and two injured (REUTERS, 2016). Imparing
the safety of life and/or damage to structure or equipment can have costly economic and
safety implications. Consequently, there is a requirement by classification societies to ensure
that an offshore facility can survive in extreme wave conditions (Lee et al., 2014, ABS, 2014,
API, 2010, DNV, 2009). The slam events and the associated forces must be correctly and
accuratley accounted for in the design stage.
The current engineering knowledge required to accurately predict the magnitude and
distribution of wave-in-deck loads and the resulting global response of a floating structures
such tension leg platforms (TLPs) and semi-submersibles remains limited. This fact is
reflected in the very limited number of papers reporting on model tests and numerical
analyses of typical multi-column floaters currently available in the open literature.
Johannessen et al. (2006) and Hennig et al. (2011) investigated the dynamic air gap, wave

3
loads and floating platform response under extreme wave conditions. Both investigations
reported that a wave-in-deck event can lead to an additional extreme response mechanism
and a step change in the extreme loading magnitude. It must be noted that complete and
detailed results of these types of experiments are usually subjected to project confidentiality
requirements and are therefore not available in the public domain.
Model tests are arguably the best approach for estimating wave-in-deck loads (Scharnke et
al., 2014). However, this approach is costly, time-consuming and involves a number of
drawbacks such as scaling effects. Alternatively, the use of computational fluid dynamics
(CFD) based methods for calculating wave induced loads on offshore structures has been
increasing. Commonly used commercial codes such as STAR-CCM+ and ANSYS FLUENT
are available for modelling and solving wave-in-deck impact problems using the volume of
fluid (VOF) method to capture free-surface hydrodynamic flows (CD-Adapco, 2012, Fluent,
2009). Recently, a robust overset grid technique has been developed to allow for numerical
models with six degrees of freedom (6DOF) (Chen et al., 2008). Unlike traditional mesh
techniques such as dynamic mesh, the mesh in the overset grid technique does not defrom
and thereby remeshing is not required. The technique can therefore be used for modelling
large amplitude motions such as the case of the surge motion in TLPs. Nevertheless, any new
CFD simulation technique can only be trusted by the industry if its results have been
thoroughly validated against experimental data first.
There is a large body of work on CFD investigations of wave impact loads on fixed deck
structures (Abdussamie et al., 2014b, Birknes-Berg and Johannessen, 2015, Iwanowski et al.,
2014, Ren and Wang, 2004). However very little work on fixed with columns and floating
structures has been reported to date. Buchner and Bunnik (2007) employed an improved VOF
(iVOF) method implemented in ComFLOW for solving the dynamic response of the
SNORRE-A TLP subjected to extreme regular waves. Rudman and Cleary (2013) employed

4
the Smoothed Particle Hydrodynamics (SPH) technique to simulate the fully non-linear
dynamics of a large breaking wave hitting a TLP. These numerical studies (Buchner and
Bunnik, 2007, Rudman and Cleary, 2013) were not validated against model tests. Wu et al.
(2014) conducted a numerical study using STAR-CCM+ to investigate the air gap of a TLP
under irregular extreme waves by applying the same input wave signal used in the model test.
Each wave signal required 20 or more iterations in order to achieve a satisfactory match
between measurements and numercial results. This implies that their proposed CFD
technique is still too time expensive to be used for practical applications (Birknes-Berg and
Johannessen, 2015).
The literature review discussed above showed that there are no detailed, combined numerical-
experimental wave-in-deck investigations on floating offshore structures available for
scientific research in the public domain. Therefore, the objective of this study is to investigate
the problem in a systematic way by introducing both experimental and numerical procedures.
The scope of the present investigation is to examine the global response of a conventional
TLP at a model scale of 1:125 due to extreme wave events corresponding to a 10,000-year
cyclonic condition. Regular wave tests were conducted in the Australian Maritime College
(AMC) towing tank. Using data from repeated runs, uncertainity tests of wave elevations,
tendon tensions, surge motion and slam pressures at the deck underside were performed. In
addition, the commercial CFD code STAR-CCM+ was used to investigate the characteristics
of unidirectional regular wave impact on the model. The overset grid technique was used to
model rigid body motions. The TLP tendons were modelled using masless spring lines. The
numerical results were then validated against the measurements acquired in model tests.
Experimental investigation
Experimental setup
The TLP model was divided into two parts namely a hull module (columns and pontoons)
and a topside deck module. The TLP hull module was represented by four circular columns

5
and four square pontoons; the scaled model dimensions were based on the SNORRE-A TLP
(Almeland et al., 1991). The main principles of the structure are given in Table 1. A square
deck box of 608 mm 608 mm and 210 mm high was constructed (Figure 1). Previous
studies examined the deck individually and the deck and hull as a combined structure
(Abdussamie et al., 2016a, Abdussamie et al., 2016b). The operating scaled draft was
maintained and the resulting static deck clearance, i.e., the vertical distance from the still-
water level (SWL) to the deck underside, was 120 mm (15.0 m full scale), as given in Table
1. The 1:125 water depth does not represent the actual operational water depth of SNORRE-
A, this was due to the limitations imposed by the maximum operational water depth of the
towing tank of 1.5 m (Abdussamie et al., 2016a).
Table 1. Key principles for SNORRE-A TLP at full and model scales.
Parameter
Full scale
Tested model scale
Column diameter
25.00 m
200 mm
Pontoon size, height width
11.50 x 11.50 m
92 x 92 mm
Column spacing
76.00 m
608 mm
Column height
63.00 m
505 mm
Deck size, length breadth height
124.5 92.0 15.0 m
608 608 210 mm
Deck clearance, a
0
27.00 m
120 mm
Platform draft
38.125 m
305 mm
Displacement
101840 t
52.15 kg
Total mass
77640 t
39.75 kg
Initial pretension per leg, T
o
6055 t
3.10 kg
Number of tendons per leg, n
4
1
Total tendon length at zero offset, L
o
307 m
1195 mm
Axial stiffness per leg, nEA/L
o
2.42 10
8
N/m
15.80 N/mm
Riser tension
3320 t
1.70 kg
Centre of gravity, C
g
(x, y, z)
n/a
(0.0, 0.0, 5.0) mm
Mass moment of inertia (I
xx,
I
yy,
I
zz
)
n/a
(5.23, 5.23, 5.63) kg.m
2
Water depth
310.00 m
1500 mm
Figure 1.
The rotation point of the tendons at the TLP model end was located at the column base. For
that purpose a hinge was installed for each column at z = -310 mm, i.e., the model’s keel

Citations
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Journal ArticleDOI
Abstract: Model tests were conducted to investigate the global response of a conventional tension leg platform (TLP) due to wave-in-deck loads associated with extreme wave events in irregular long-crested waves of a cyclonic sea state. The experimental setup was designed to allow for the simultaneous measurement of wave surface elevations, rigid body motions, tendon tensions, as well as the pressure distribution at the model's deck underside. The obtained results demonstrated the variability of all the measurements and provided insights into the effect of wave-in-deck loads on the platform behaviour, tendon tensions and slamming pressures and showed qualitative correlations between these parameters. Based on the repeated tests in several events with different wave parameters, general observations and conclusions were made with respect to the platform dynamics during the deck impact, tendon tensions, slack tendon situations, tendon ringing and local impact pressures. The results of this study could be used for calibrating computational fluid dynamics (CFD) tools.

12 citations


Cites background or result from "Experimental investigation of extre..."

  • ...This finding is supported by the results of experimental studies (Abdussamie et al., 2016a, 2016b; Scharnke et al., 2014; Scharnke and Henning, 2015) on the wave-in-deck impact problems of fixed decks, which determined Fig....

    [...]

  • ...…the columns and pontoons of a multi-column platform such as tension leg platform (conventional TLP), the diffraction and radiation effects can cause the wave elevation to increase and locally impact the lower deck (Niedzwecki and Huston, 1992; Scharnke and Hennig, 2015; Abdussamie et al., 2016a)....

    [...]

  • ...Having these separate modules allowed testing of the deck individually and the deck and hull as a combined structure (Abdussamie et al., 2016a, 2016b)....

    [...]

  • ...Findings from other recent studies (Abdussamie et al., 2016a, 2016b; Scharnke et al., 2014; Scharnke and Henning, 2015) into the wave-in-deck impact problems of fixed decks identified the downward force on the deck alone, the magnitude of which can be as large as the upward force component....

    [...]

  • ...Scharnke et al. (2014) and Abdussamie et al. (2016a, 2016b) attributed the large magnitude of the downward force to the added mass surrounding the deck structure, in both x and z directions, which is accelerated downwards at this time....

    [...]


Journal ArticleDOI
01 Feb 2017
Abstract: This article describes a series of model tests conducted to examine extreme wave events associated with tropical cyclonic conditions and their impacts on an offshore deck structure. Extreme waves of a representative cyclonic sea state were examined in a towing tank within long-crested irregular wave trains. Experimental results presented include global forces and localised slamming pressures acting on a rigidly mounted box-shaped deck, which represents a simplified topside structure of a tension leg platform. The effect of static set-down on the still-water air gap was investigated by applying an equivalent reduction for the deck clearance. It was found that a small reduction of 20 mm (2.5 m full scale) in the original deck clearance can lead to a doubling of the magnitude of the horizontal force and the vertical upward-directed force components, as well as significantly increased slamming pressures in many locations on the deck underside.

8 citations


Cites background from "Experimental investigation of extre..."

  • ...Since a small change in crest height can lead to a considerable variation in the associated wave impact forces and slamming pressures, accurate measurement of the wave height was critical.(31) Consequently, the wave crests of each wave event were identified from the measured wave elevation time histories with and without the deck structure (at different deck clearances, a0)....

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Journal ArticleDOI
Abstract: This paper presents an experimental and numerical investigation into the magnitude and distribution of the hydrodynamic loads affecting a fixed multicolumn offshore platform (rigidly mounted tension leg platform) when subjected to extreme wave events All wave load components, including wave-in-deck slamming pressures, were predicted using a commercial computational fluid dynamics (CFD) code STAR-CCM+ and compared against experimental measurements Slamming pressures were calculated using both data obtained locally at discrete points and globally averaged over the whole exposed area of the deck In all simulated cases, the deck area exposed to a wave-slamming event was found to be in contact with a water–air mixture with a significant proportion of air phase It was concluded that the slamming pressure data for the exposed area provided better insights into the pressure changes due to air compressibility and its content

4 citations


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  • ...All details of model’s dimensions and instrumentation, as well as the experimental setup, can be found in the open literature (Abdussamie et al., 2016a, Abdussamie et al., 2016b)....

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Journal ArticleDOI
Abstract: This study investigates the freak wave impinging on a tension-leg platform through wave flume experiments. The freak waves are generated using the focused wave theory. By adjusting the wave focusing location, different incident wave scenarios at the structure location are produced. Simultaneous measurements of wave shape evolutions upon impingement, wave impact pressures on the platform deck, platform motions and tether forces are carried out for synchronized analyses of the wave kinematics/dynamics and structural responses. The variation of these parameters with the incident wave profile is studied. It is found that although applying less intensive local impact pressures as compared to the highly-breaking freak wave, the slightly-breaking or non-breaking freak wave imposes the same level of adverse effect on the platform's global stability in terms of motions and tether forces. In addition, the high-crest freak wave causes violent motions of the floating platform, which are likely to induce snap loads of large amplitude and high occurrence frequency in tethers. The published results would provide useful benchmarks for validating numerical and analytical models.

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Abstract: The design of deep water offshore platforms requires the analysis of wave-structure interaction phenomena which have not been as critical for shallower water platform designs In the case of tension leg platforms (TLPs) interaction phenomena such as wave run-up on the vertical legs and the amplification of the waves beneath the deck are major design considerations The research investigation reported here focuses on a series of small scale wave tank tests on four column TLP models examining these phenomena The role of vertical leg spacing and comparative tests of the TLP models with and without pontoons was investigated As the vertical legs were moved closer an increase in wave run-up and a shifting of the incident wave period corresponding to the maximum wave upwelling were noted Comparisons with wave measurements for single cylinders from previous experimental studies and the TLP configurations used in this study are presented A design formula for estimating wave run-up on TLPs is suggested based upon these experiments The wave run-up on a leg directly in the wake of another leg is presented A comparison of the wave upwelling measurements with previously published numerical results are discussed A wave uplift force model which allows for the inclusion of the experimentally obtained wave upwelling measurements is presented and discussed with regard to the design specification of platform deck elevation

44 citations


"Experimental investigation of extre..." refers background in this paper

  • ...wave upwelling has been observed in many tank experiments (Niedzwecki and Huston 1992)....

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  • ...For large multi-column platforms, a local amplification of the wave field i.e. wave upwelling has been observed in many tank experiments (Niedzwecki and Huston 1992)....

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  • ...However, under deck structures, such as columns and pontoons, can affect the force magnitude and its distribution on the upper deck structure (Niedzwecki and Huston 1992; Scharnke and Hennig 2015)....

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01 Sep 2009-Energy
Abstract: Hurricanes Ivan, Katrina, and Rita passed through the Gulf of Mexico during 2004 and 2005 and resulted in the largest number of destroyed and damaged offshore oil and gas structures in the history of Gulf operations. In the final official government assessment, a total of 126 platforms were destroyed and over 183 structures were identified as having extensive damage. Production associated with wells and structures that are not redeveloped are classified as lost. The purpose of this paper is to derive functional relations that describe the likely contribution the collection of destroyed assets would have made to future production in the Gulf of Mexico. We estimate that the total remaining reserves from the set of destroyed structures range in value between $1.3 and $4.5 billion depending on the assumptions employed. We summarize the impact of the storms on the Gulf of Mexico oil and gas infrastructure and discuss the main issues involved in redevelopment decision making. A meta-model analytic framework is applied to perform sensitivity analysis and to explore the interactions of assumptions on model output. A discussion of the limitations of the analysis is presented.

27 citations


"Experimental investigation of extre..." refers background in this paper

  • ...Insufficient air gap has been outlined to be one of the major causes for many sustained damages, for instance, in the North Sea (Kvitrud et al. 2001) and in the Gulf of Mexico (Kaiser et al. 2009)....

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"Experimental investigation of extre..." refers background in this paper

  • ...The Joint North Sea Wave Project (JONSWAP) spectrum was utilised for a representative 10,000-year sea state asso- ciated with Australian cyclonic condition: Hs = 22.13 m, Tp = 17.0 s (Tp / √ Hs = 3.61)....

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  • ...Insufficient air gap has been outlined to be one of the major causes for many sustained damages, for instance, in the North Sea (Kvitrud et al. 2001) and in the Gulf of Mexico (Kaiser et al. 2009)....

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15 citations


"Experimental investigation of extre..." refers background in this paper

  • ...…been carried out to estimate vertical wave-in-deck force on different types of fixed structures e.g. on a flat plate subjected to regular waves (Bhat 1994) and random waves (Sun et al. 2011), and on a horizontal box-type deck structure due to regular waves (Baarholm 2009; Abdussamie et al. 2014a)....

    [...]

  • ...2011), and on a horizontal box-type deck structure due to regular waves (Baarholm 2009; Abdussamie et al. 2014a)....

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Frequently Asked Questions (2)
Q1. What have the authors contributed in "Wave-in-deck loads and response of a tlp model in unidirectional regular waves" ?

In this paper, the authors used a robust overset grid technique for modeling and solving wave-in-deck impact problems using the volume of fluid ( VOF ) method. 

The present numerical study using regular wave conditions validated against model tests could serve as a benchmark validation case for further numerical studies aimed at predicting wave-in-deck loading due to, e. g., combined waves with current and/or wind.