Investigation on the Effects of Risers in the Dynamics of Floating Systems

2010 ◽  
Author(s):  
Felipe Rateiro ◽  
Edgard Borges Malta ◽  
Andre´ L. C. Fujarra ◽  
Daniel Prata Vieira ◽  
Kazuo Nishimoto
Keyword(s):  
Dynamic Behavior ◽  
Large Diameter ◽  
Model Tests ◽  
Towing Tank ◽  
Dynamic Simulator ◽  
Offshore Industry ◽  
Technological Research Institute ◽  
The University ◽  
Floating Systems ◽  
Significant Increment

This paper presents the experimental results obtained from the model tests performed at the IPT (State of Sa˜o Paulo Technological Research Institute) towing tank, located in Sa˜o Paulo, Brazil. The model used was the semi-submersible ITTC-SR192, at a scale 1:105. The main focus of this study is the analysis of the risers influence on the floating unit dynamics, taking into account damping effects caused by the lines. In order to establish basis of comparison the tests were performed with and without risers. These were modeled as a group of large diameter hoses that are able to provide a significant increment in the damping of the system. By such approach, it was possible to evaluate the changes on the dynamic behavior of the unit induced by the presence of risers. As an additional investigation tool, these results were analyzed with the aid of the software Numerical Offshore Tank (Tanque de Provas Nume´rico - TPN), which is a dynamic simulator of offshore systems based on parallel-processing developed by means of a partnership between the University of Sa˜o Paulo, Petrobras and other Brazilian research institutions. By means of the comparisons between the model tests results with and without risers and of the results from the numerical tool, TPN, the dynamic behavior of the floating unit was investigated in terms of the effects caused by the presence of risers, which is a very relevant subject as offshore industry walks towards ultra-depth waters.

Design of the University of New Orleans Ship-Offshore University Laboratory for Offshore Industry Support

1988 ◽  
Vol 110 (3) ◽  
pp. 133-140 ◽  
Author(s):  
R. Latorre
Keyword(s):  
New Orleans ◽  
Water Current ◽  
Offshore Structure ◽  
Water Research ◽  
Towing Tank ◽  
Calm Water ◽  
Tank Design ◽  
Offshore Industry ◽  
The University ◽  
University Laboratory

On July 23, 1987, the University of New Orleans (UNO) dedicated its new Engineering Building, which houses a 38.3 m×4.57 m×0–2.134 m deep ship-offshore university laboratory tow tank. This paper covers the initial stages of the project and summarizes the towing tank design for ship-offshore testing. The tank is configured for three purposes: 1) conventional ship research in deep water with calm water or waves; 2) offshore structure testing with provision for observation and anchoring; 3) shallow water research in calm water, current, and waves.

Investigation on the Effects of Current in the Dynamics of Floating Systems

2011 ◽  
Author(s):  
Felipe Rateiro ◽  
Edgard Borges Malta ◽  
Andre´ L. C. Fujarra
Keyword(s):  
Dynamic Behavior ◽  
Potential Theory ◽  
Model Tests ◽  
Experimental Results ◽  
Numerical Code ◽  
Additional Investigation ◽  
Floating Systems ◽  
Investigation Procedure

This paper presents the experimental results obtained by means of model tests, focused on the analysis of the influence of current effects in the dynamic behavior of a semi-submersible. The tests were accomplished with and without current, in order to establish the comparison basis. As an additional investigation procedure, the experimental results were compared to a numerical code based on the potential theory. As will be seen, considerable changes in the natural periods and in the damping levels was observed.

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.

Experimental Study of a Tanker Ship Squat in Shallow Water

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Mohammadreza Fathi Kazerooni ◽  
Mohammad Saeed Seif
Keyword(s):  
Experimental Study ◽  
Shallow Water ◽  
Experimental Approach ◽  
Model Tests ◽  
Ship Hull ◽  
Experimental Results ◽  
Shallow Waters ◽  
Towing Tank ◽  
Ship Model

One of the phenomena restricting the tanker navigation in shallow waters is reduction of under keel clearance in the terms of sinkage and dynamic trim that is called squatting. According to the complexity of flow around ship hull, one of the best methods to predict the ship squat is experimental approach based on model tests in the towing tank. In this study model tests for tanker ship model had been held in the towing tank and squat of the model are measured and analyzed. Based on experimental results suitable formulae for prediction of these types of ship squat in fairways are obtained.

Experimental Analysis of Five Keel-Hull Combinations

1985 ◽  
Author(s):  
J. Gerritsma ◽  
J. A. Keuning
Keyword(s):  
Experimental Analysis ◽  
Model Tests ◽  
Experimental Results ◽  
Forward Speed ◽  
Hull Form ◽  
Towing Tank ◽  
Side Force ◽  
Performance Predictions

Model tests with five different keels in combination with one particular hull form have been carried out in the Delft Towing Tank. The variations include a plain deep keel, a keel-centre board, a plain restricted draft keel,a "Scheel" keel and a "winglet" keel. Based on the experimental results performance predictions are given for a 63 ft yacht for windspeeds up to 25 knots. The measured side force and resistance as a function of heeling angle, leeway angle and forward speed are used to analyse the relative merits of the considered keel-hull combinations.

Water Waves and Marine Structure Interaction

2004 ◽  
Author(s):  
Octavi Sado´ Garriga ◽  
Jeffrey M. Falzarano
Keyword(s):  
Free Surface ◽  
New Orleans ◽  
Water Waves ◽  
Frequency Estimation ◽  
Experimental Results ◽  
Oscillating Water Column ◽  
Towing Tank ◽  
Structure Interaction ◽  
Marine Structure ◽  
The University

The purpose of this paper is to combine and extend existing potential flow theory in order to analyze the linear free surface problem of an Oscillating Water Column (OWC) device and apply it to moonpool design. Analytical results were obtained implementing the previously derived theories, and later compared to experimental results conducted at the University of New Orleans Towing Tank. The model tests consisted of a study of a cylindrical OWC. The theoretical and experimental results of the free surface for the OWC tests agree for the resonant frequency estimation response but they disagree on the amplitude of the response.

Experimental Investigation on Resistance Reduction by Means of Air-Bubbling Technique

2018 ◽  
Author(s):  
Enrico Ravina ◽  
Sofia Guidomei
Keyword(s):  
Flow Rate ◽  
Low Cost ◽  
Frictional Resistance ◽  
Flat Plates ◽  
Research Activity ◽  
Frictional Drag ◽  
Towing Tank ◽  
Resistance Reduction ◽  
The University ◽  
Different Levels

The paper refers on a research activity, focused at DREAMS Lab of the University of Genoa (Italy) and still under development, oriented to experimental application of air-bubbling techniques on flat plates and hull models. In this study the reduction in the frictional resistance by air bubbling generated by customized pneumatic circuits is tested, both on the lower surfaces of flat plates characterized of different geometries of holes and on a hull model tested in towing tank. The effective shape of air bubbles is observed, and changes in the local frictional drag are measured, using flexible and low cost thin sensors at different levels of flow rate and pressure of injected air. In towing tank tests the experiments compare hull without and with holes on the bottom, modifying the characteristics of speed, pressure, flow rate and areas interested to the air injection. Systematic tests campaign has been developed, using also actuation pneumatic workbenches expressly designed for the experiments.

Thorough Verification and Validation of CFD Simulation for FPSO Roll Damping

2019 ◽  
Author(s):  
Donghwan Lee ◽  
Zhenjia (Jerry) Huang
Keyword(s):  
Numerical Modeling ◽  
Cfd Simulation ◽  
Development Project ◽  
Model Tests ◽  
Design Tool ◽  
Verification And Validation ◽  
Empirical Formulas ◽  
Roll Damping ◽  
Calm Water ◽  
Offshore Industry

Abstract For floating production platform such as FPSO and FLNG, it is important to use confidently estimated roll damping coefficients in the prediction of its motions in waves since in many cases the roll response is mainly contributed from resonance. Traditionally roll damping prediction was made through model tests or empirical formulas. As computing power and numerical modeling techniques have been improved during last a few decades, offshore industry starts to consider CFD as an alternative engineering and design tool complementary and/or supplementary to physical model tests. This paper presents our verification and validation work of modeling practices with commercially available CFD software for engineering applications for FPSO roll decay damping in calm water. The numerical modeling followed a recommended modeling practice developed by a Joint Development Project – TESK JDP [1].

The Ocean Cleanup System 001 Performance During Towing and Seakeeping Tests

2019 ◽  
Author(s):  
Joost Sterenborg ◽  
Nicola Grasso ◽  
Rogier Schouten ◽  
Arjen Tjallema
Keyword(s):  
Fluid Structure Interaction ◽  
Model Tests ◽  
Operating Conditions ◽  
Image Correlation ◽  
Plastic Pollution ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Floating System ◽  
Floating Systems

Abstract One of the aims of The Ocean Cleanup is to develop technologies to extract plastic pollution from the world’s oceans. Several concepts of passive floating systems were considered that are supposed to confine plastics to ease their collection. Such concepts consist of a floating member and a submerged flexible skirt and have in common that their span is generally more than 500 meters. Consequently, fluid-structure interaction plays an important role in the response of such a floating system. To support numerical simulations, MARIN carried out extensive model tests on a 120 meter system section of the final concept, with focus on the fluid-structure interaction (FSI) of the submerged skirt in operating conditions and in towing configuration. The ability to capture plastics was not investigated in these model tests. Novel for wave-basin tests were non-intrusive measurements using underwater Digital Image Correlation (DIC) to obtain the displacements and deformations of the flexible skirt. DIC proved to be a capable measurement technique for this type of structure in combination with a wave basin. Detailed quantitative data on skirt motions and deformations were delivered and the last concept of the cleanup system was tested in the towing configuration and operational configuration.

1 g Model Tests on the Displacement Accumulation of Large-Diameter Piles Under Cyclic Lateral Loading

2017 ◽  
Vol 40 (2) ◽  
pp. 20160102 ◽  
Author(s):  
J. Albiker ◽  
M. Achmus ◽  
D. Frick ◽  
F. Flindt
Keyword(s):  
Large Diameter ◽  
Model Tests ◽  
Lateral Loading
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