Analysis of the Tunnel Immersion for the Busan-Geoje Fixed Link Project Through Scale Model Tests and Computer Simulations

2009 ◽  
Author(s):  
Hans Cozijn ◽  
Jin Wook Heo
Keyword(s):  
Simulation Model ◽  
Computer Simulations ◽  
Time Domain ◽  
Extreme Values ◽  
Sensitivity Study ◽  
Model Tests ◽  
Direct Access ◽  
Scale Model ◽  
Mooring System ◽  
Sea Bed

In Korea a four lane motorway is constructed between the city of Busan and the island Geoje, reducing traveling times from 1 hour by ferry to just 10 minutes by car. The so-called Busan-Geoje Fixed Link consists of 2 cable-stayed girder bridges and a tunnel, crossing the bay of Jinhae. The submerged tunnel is built by transporting each of its 18 elements below 2 pontoons from a construction dock to their final positions and lowering them on the sea bed. The project is unique, because the tunnel elements are installed in a bay with direct access towards open sea. For this reason, the effects of incoming swells and wind seas were investigated in detail, so that the operational limits of the tunnel element immersion could be accurately determined. This was achieved by using an approach of combined hydrodynamic scale model tests and time-domain computer simulations. First, scale model tests were carried out in MARIN’s Shallow Water Basin. A detailed test set-up was constructed, including the trench in which the tunnel elements are placed, as is shown in the photograph. Models of a tunnel element, two pontoons, the mooring system, contraction lines and suspension wires were constructed at a scale of 1:50. The motions of the pontoons and the submerged tunnel element, as well as the tensions in the lines, were measured in a range of different wave conditions. Different stages of the tunnel immersion were investigated. Second, a simulation model of the pontoons and tunnel element was constructed in MARIN’s time-domain simulation tool aNySIM. The large number of mooring lines, contraction lines and suspension wires resulted in a relatively complex numerical model. The simulation model was calibrated such that the results from the model tests could be accurately reproduced. Subsequently, a sensitivity study was carried out, investigating the parameters most critical to the operation and the mooring system of the pontoons was further optimized. Finally, the operational limits of the tunnel immersion were evaluated by carrying out more than 6,500 time-domain simulations, investigating a large number of different combinations of wind sea and swell. The simulation results included motions, velocities and accelerations, as well as line tensions. The extreme values were used to perform a combined evaluation of more than 10 structural and operational criteria. The photograph below (copyright Peter de Haas, Royal Haskoning) shows the immersion of the first of 18 tunnel elements in the bay of Jinhae, in February 2008.

Conceptual Design and Model Tests for a Mid-Water Floating Hyperloop Tunnel

2020 ◽  
Author(s):  
L. J. Kemp ◽  
W. J. Otto ◽  
O. J. Waals
Keyword(s):  
Conceptual Design ◽  
High Speed ◽  
Optical Measurement ◽  
Model Tests ◽  
Scale Model ◽  
Mooring Line ◽  
Mooring System ◽  
Tunnel Length ◽  
Greenhouse Gasses ◽  
Global Emission

Abstract Aviation has a significant impact on the global emission of greenhouse gasses. On the Northern Atlantic route alone there are over 2,500 crossings daily. This illustrates the high demand for connecting people. It is expected that this demand will only increase in the future, which will increase the emissions due to aviation even further. An alternative way for connecting people can be the hyperloop, which obtains comparable speeds while using a fraction of the energy. For intercontinental connections a tunnel would be necessary. In this study, a conceptual design of a mid-water floating hyperloop tunnel is made and tested on model scale at MARIN. In the present paper the results are discussed of model tests on a mid-water floating tunnel in Atlantic storm conditions at various wave directions and tunnel depths. The conceptual design of the tunnel is based on (nearly) available technology. One kilometer tunnel segments with a diameter of 11 m are connected to construct a tunnel length of > 5,000 km. Model basin tests are performed on scale 1:110, where a scale model of 140 m length is tested. The tunnel is designed as a neutral buoyant tunnel to reduce complexity and costs for the mooring system. The motions, deformations and mooring line tensions for the tunnel segments are measured by force transducers, accelerometers and an optical measurement system. Due to flexibility of the slender tunnel segments in combination with a soft mooring system, the tunnel tends to following the incoming waves for certain tunnel depths and wave directions. Only small motions and deformations are allowed for a hyperloop capsule to travel on high speed. The conceptual tests show first results on tunnel depth, structural and geometrical design of an hyperloop tunnel and mooring system.

Comparison Between Numerical Prediction and Model Tests Measurements on the Centerwell Tank of a Radial Wellbay Spar

2012 ◽  
Author(s):  
Edmund Muehlner ◽  
John Murray ◽  
Surya Banumurthy ◽  
Chandan Lakhotia
Keyword(s):  
Time Domain ◽  
Accurate Estimate ◽  
Model Tests ◽  
Scale Model ◽  
Inertia Effect ◽  
Primary Difference ◽  
Truss Spar ◽  
Interior Walls ◽  
Six Degree Of Freedom ◽  
Semi Empirical

The radial wellbay (RAW) Spar is, for the most part, based on conventional Truss Spar technology. The primary difference between the RAW Spar and the conventional Truss Spar is the wellbay arrangement. An integral structural component of the RAW Spar is the ABCD (Adjustable Buoyancy Centerwell Device) located in the lower portion of the centerwell. The ABCD is connected to the interior of the hard tank using a number of shear plates. The ABCD captures the buoyancy in the open centerwell and contributes to the total buoyancy of the hard tank. As an option, the ABCD can be used for in-hull storage. On the RAW drilling Spar, the ABCD can be used to support the setback and pipe racking system. Design applications using the ABCD raise an additional requirement in the design of the hard tank, specifically, an accurate estimate of the load in the structure that connects the ABCD to the hard tank. Contributions to this load come from the inertia effect of the Spar motions, hydrostatic responses affected by ballast conditions in the device, and hydrodynamic forces affected by pressure in the riser slot gap. Connection loads are required to design the structure connecting the ABCD to the interior walls of the hard tank. An ABAQUS™ based time domain semi-empirical model was developed to predict the local and global loads on the ABCD. A series of 1:50 scale model tests on the RAW Spar were carried out at the OTRC basin in College Station, Texas. The model’s ABCD, mounted on a dynamometer system inside the hard tank, was used to measure the six-degree-of-freedom forces between the hard tank and the ABCD. The paper focuses on a comparison of the predicted and measured loads.

Numerical Simulations and Truncation Design of a Deepwater Internal Turret FPSO Before Model Test

2010 ◽  
Author(s):  
Hongwei Wang ◽  
Yong Luo ◽  
Xiaoming Cheng
Keyword(s):  
Numerical Simulations ◽  
Model Test ◽  
Time Domain ◽  
Model Tests ◽  
Test Model ◽  
Mooring System ◽  
Static Characteristics ◽  
Mooring Lines ◽  
Horizontal Dimension ◽  
The Time Domain

Model tests of an internal turret moored deepwater FPSO will be conducted in the deepwater offshore basin recently completed in Harbin Engineering University. Considering the limitations of the basin facilities and to reduce the complexity of fixing risers on the basin bottom, the 13 risers are simplified and combined to 4 risers. In addition, the horizontal dimension of the basin is not able to accommodate mooring system at the test model scale. Therefore, certain mooring lines have to be truncated. Two truncation methods are proposed according to the similitude of static characteristics of the mooring system. The first method only truncates the portion of the line that lies on the seabed and the second method truncates the suspended line portion. Numerical simulations have been carried out in the time domain with mooring lines coupled with FPSO. The calculated results are found to agree well with those of the prototype mooring system. Both truncation methods are found to be robust and reliable which provide a valuable reference for the forthcoming model tests.

Time Domain Simulation Model for Research Vessel Gunnerus

2015 ◽  
Author(s):  
Vahid Hassani ◽  
Andrew Ross ◽  
Ørjan Selvik ◽  
Dariusz Fathi ◽  
Florian Sprenger ◽  
...  
Keyword(s):  
Simulation Model ◽  
Time Domain ◽  
Trial Data ◽  
Full Scale ◽  
Dynamic Equations ◽  
Scale Model ◽  
Research Vessel ◽  
Oil Exploration ◽  
Time Domain Simulation ◽  
Sea Trial

A research vessel (RV) plays an important role in many fields such as oceanography, fisheries and polar research, hydrographic surveys, and oil exploration. It also has a unique function in maritime research and developments. Full-scale sea trials that require vessels, are usually extremely expensive; however, research vessels are more available than other types of ship. This paper presents the results of a time-domain simulation model of R/V Gunnerus, the research vessel of the Norwegian University of Science and Technology (NTNU), using MARINTEK’s vessel simulator (VeSim). VeSim is a time-domain simulator which solves dynamic equations of vessel motions and takes care of seakeeping and manoeuvring problems simultaneously. In addition to a set of captive and PMM tests on a scale model of Gunnerus, full-scale sea trials are carried out in both calm and harsh weather and the proposed simulation model is validated against sea trial data.

Coupled Mooring Analysis and Large Scale Model Tests on a Deepwater Calm Buoy in Mild Wave Conditions

2002 ◽  
Author(s):  
T. H. J. Bunnik ◽  
G. de Boer ◽  
J. L. Cozijn ◽  
J. van der Cammen ◽  
E. van Haaften ◽  
...  
Keyword(s):  
Model Tests ◽  
Irregular Waves ◽  
Scale Model ◽  
Mooring Line ◽  
Wave Forces ◽  
Mooring System ◽  
Mooring Lines ◽  
Pitch Moment ◽  
Numerical Tool ◽  
Decay Tests

This paper describes a series of model tests aimed at gaining insight in the tension variations in the export risers and mooring lines of a CALM buoy. The test result were therefore not only analysed carefully, but were also used as input and to validate a numerical tool that computes the coupled motions of the buoy and its mooring system. The tests were carried out at a model scale of 1 to 20. Captive tests in regular and irregular waves were carried out to investigate non-linearities in the wave forces on the buoy for example from the presence of the skirt. Decay tests were carried out to determine the damping of the buoy’s motions and to obtain the natural periods. Finally, tests in irregular waves were carried out. The dynamics of the mooring system and the resulting damping have a significant effect on the buoy’s motions. A numerical tool has been developed that combines the wave-frequency buoy motions with the dynamical behaviour of the mooring system. The motions of the buoy are computed with a linearised equation of motion. The non-linear motions of the mooring system are computed simultaneously and interact with the buoy’s motions. In this paper, a comparison is shown between the measurements and the simulations. Firstly, the wave forces obtained with a linear diffraction computation with a simplified skirt are compared with the measured wave forces. Secondly, the numerical modelling of the mooring system is checked by comparing line tensions when the buoy moves with the motion as measured in an irregular wave test. Thirdly, the decay tests are simulated to investigate the correctness of the applied viscous damping values. Finally, simulations of a test in irregular waves are shown to validate the entire integrated concept. The results show that: 1. The wave-exciting surge and heave forces can be predicted well with linear diffraction theory. However, differences between the measured and computed pitch moment are found, caused by a simplified modelling of the skirt and the shortcomings of the diffraction model. 2. To predict the tension variations in the mooring lines and risers (and estimate fatigue) it is essential that mooring line dynamics are taken into account. 3. The heave motions of the buoy are predicted well. 4. The surge motions of the buoy are predicted reasonably well. 5. The pitch motions are wrongly predicted.

Motions and Mooring Loads of an LNG-Carrier Moored at a Jetty in a Complex Bathymetry

2009 ◽  
Author(s):  
Otto Weiler ◽  
Hans Cozijn ◽  
Bas Wijdeven ◽  
Stephane Le-Guennec ◽  
Franc¸ois Fontaliran
Keyword(s):  
Computer Simulations ◽  
Environmental Conditions ◽  
Low Frequency ◽  
Model Tests ◽  
Scale Model ◽  
Incoming Wave ◽  
Wave Conditions ◽  
The Republic ◽  
The Time Domain ◽  
Comparison Of The Results

The Yemen LNG Company Ltd. is working on the design and construction of an LNG plant in the Republic of Yemen. The LNG plant, located at Balhaf on the Gulf of Aden, includes a jetty approximately 750 m from the shore to allow loading of LNG carriers. The bathymetry around the jetty is very complex and includes a large variation in water depth along the berth. Furthermore a cape near the jetty affects the incoming wave conditions. Deltares (formerly WL | Delft Hydraulics), together with MARIN, carried out a study of combined hydrodynamic scale model tests and computer simulations. The aim of the project was to determine the limiting environmental conditions for safe mooring of the LNG carriers at the jetty. The hydrodynamic scale model tests at Deltares focused on an accurate modeling of the wave conditions at the jetty and the motion response of the moored ship. To achieve this, the bathymetry around the jetty was modeled in detail, including the cape partially shielding the jetty from incoming waves from the open sea. Wind was applied to the moored ship as constant forces. The time-domain computer simulations were carried out by MARIN, using their TERMSIM simulation model. After calibration against scale model test results, the numerical model was used to quantify the effect of gusting wind for all environmental conditions and all ships as tested in the basin. The results of the scale model tests, corrected for the effect of gusting wind, indicated that the vessel can stay safely moored at the jetty in quite severe conditions. This leads to a high jetty availability, which is a favorable outcome of the project. After describing, in a general way, the methodology and results of the project, this paper focuses on the comparison of the results of the model tests with those of the computer simulations. This comparison showed that the low frequency effects, both excitation and response, in the complex bathymetry that was considered here, are very complex and beyond the present numerical modeling capabilities. Therefore, in the short term, physical model testing will remain necessary for an accurate prediction of the moored ship’s response in such situations. For the longer term the development of additional analysis and simulation methods is required.

Octabuoy SDM: A Compact Semi-Submersible Design for Deepwater Applications

2005 ◽  
Author(s):  
Florus Korbijn ◽  
Ida Husem ◽  
Erik Pettersen
Keyword(s):  
West Africa ◽  
Gulf Of Mexico ◽  
Time Domain ◽  
Weight Ratio ◽  
Model Tests ◽  
Mooring System ◽  
Steel Catenary Risers ◽  
Loop Currents ◽  
Motion Characteristics ◽  
Theoretical Considerations

A new floater concept based on proven technology but combining this technology in a novel way has been designed for Deepwater operation in the Gulf of Mexico and other deepwater locations. The Octabuoy SDM (Shallow Draught, Mooring assisted) is a semi-submersible with a design and a tuned mooring system that ensure improved motion characteristics compared to other semi-submersibles. This makes the floater very well suited for accommodating Steel Catenary Risers (SCRs) in the Gulf of Mexico and dry tree solutions for West Africa. Motion results calculated for a typical Gulf of Mexico wave environment, using a coupled time domain approach are confirmed by extensive model testing of the concept, which proves the ability of the proposed concept to accommodate SCRs specifically for the Gulf of Mexico. Because of its relative shallow draught (23m) the platform is less susceptible to vortex induced motions (VIM) in loop currents compared to SPAR and other deep draught floaters. Theoretical considerations and model tests have proved the favorable platform behavior with respect to VIM. The Octabuoy SDM has a favorable topside load-to-hull weight ratio, which makes it a highly competitive solution compared to other semi-submersibles. Another advantage is that the platform may be outfitted and commissioned quayside.

scholarly journals Design and Automated Optimization of an Internal Turret Mooring System in the Frequency and Time Domain

2021 ◽  
Vol 9 (6) ◽  
pp. 581
Author(s):  
Hongrae Park ◽  
Sungjun Jung
Keyword(s):  
System Design ◽  
Time Domain ◽  
Initial Conditions ◽  
Minimum Weight ◽  
Optimization Algorithms ◽  
Local Optimization ◽  
Mooring System ◽  
Floating Offshore Wind Turbines ◽  
Global And Local Optimization ◽  
Global And Local

A cost-effective mooring system design has been emphasized for traditional offshore industry applications and in the design of floating offshore wind turbines. The industry consensus regarding mooring system design is mainly inhibited by previous project experience. The design of the mooring system also requires a significant number of design cycles. To take aim at these challenges, this paper studies the application of an optimization algorithm to the Floating Production Storage and Offloading (FPSO) mooring system design with an internal turret system at deep-water locations. The goal is to minimize mooring system costs by satisfying constraints, and an objective function is defined as the minimum weight of the mooring system. Anchor loads, a floating body offset and mooring line tensions are defined as constraints. In the process of optimization, the mooring system is analyzed in terms of the frequency domain and time domain, and global and local optimization algorithms are also deployed towards reaching the optimum solution. Three cases are studied with the same initial conditions. The global and local optimization algorithms successfully find a feasible mooring system by reducing the mooring system cost by up to 52%.

scholarly journals EXTREME WAVE PRESSURES AND LOADS ON A PILE-SUPPORTED WHARF DECK - INFLUENCES OF AIR GAP AND WAVE DIRECTION

2018 ◽  
pp. 5
Author(s):  
Andrew Cornett
Keyword(s):  
Offshore Structures ◽  
Model Tests ◽  
Scale Model ◽  
Extreme Waves ◽  
Wave Direction ◽  
Coastal Structures ◽  
Extreme Wave ◽  
Wave Impact ◽  
The Past ◽  
Water Depths

Many deck-on-pile structures are located in shallow water depths at elevations low enough to be inundated by large waves during intense storms or tsunami. Many researchers have studied wave-in-deck loads over the past decade using a variety of theoretical, experimental, and numerical methods. Wave-in-deck loads on various pile supported coastal structures such as jetties, piers, wharves and bridges have been studied by Tirindelli et al. (2003), Cuomo et al. (2007, 2009), Murali et al. (2009), and Meng et al. (2010). All these authors analyzed data from scale model tests to investigate the pressures and loads on beam and deck elements subject to wave impact under various conditions. Wavein- deck loads on fixed offshore structures have been studied by Murray et al. (1997), Finnigan et al. (1997), Bea et al. (1999, 2001), Baarholm et al. (2004, 2009), and Raaij et al. (2007). These authors have studied both simplified and realistic deck structures using a mixture of theoretical analysis and model tests. Other researchers, including Kendon et al. (2010), Schellin et al. (2009), Lande et al. (2011) and Wemmenhove et al. (2011) have demonstrated that various CFD methods can be used to simulate the interaction of extreme waves with both simple and more realistic deck structures, and predict wave-in-deck pressures and loads.

Large scale model tests on Royal Schelde SES

1989 ◽  
Author(s):  
R. DE GAAIJ ◽  
E. VAN RIETBERGEN ◽  
M. SLEGERS
Keyword(s):  
Large Scale ◽  
Model Tests ◽  
Scale Model ◽  
Large Scale Model
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