Evaluation of the Dynamic Behavior of the P50 FPSO System Using Dynasim: Comparison With Experimental Results

2003 ◽  
Author(s):  
Fabio G. Palazzo ◽  
Joa˜o V. Sparano ◽  
Alexandre N. Simos ◽  
Isaias Q. Masetti ◽  
Eduardo A. Tannuri
Keyword(s):  
Dynamic Behavior ◽  
Experimental Results ◽  
Numerical Code ◽  
Mooring Line ◽  
Simulation Code ◽  
Campos Basin ◽  
Anchoring System ◽  
Under Construction ◽  
Validation Tests ◽  
The University

The P50 system is a Floating Production Storage and Offloading System under construction for future operation at Brazil’s Campos Basin, in a water depth of approximately 1200 m. The system is based on a VLCC vessel, moored in DICAS (Differential Compliance Anchoring) system and presents a reasonably large riser porch on the portside for 77 lines. In this paper the dynamic behavior of the offshore system is evaluated using Dynasim, a time-domain simulation code for moored offshore systems, developed by the University of Sa˜o Paulo and Petrobras. Simulations are compared with experimental results. Two kinds of tests were performed: “Calibration” tests were carried out in order to obtain static coefficients of the hull under isolated current and wind loads. “Validation” tests were conducted to evaluate the dynamic behavior under extreme environmental conditions combining current and wave excitation. First and second-order motions were measured as well as mooring line tensions for three different drafts of the ship. A generally good agreement was observed between numerical simulations and experimental results, reassuring the reliability of the numerical code.

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.

Time Domain Simulation of the Maneuvering of a Vessel in a Seaway

2009 ◽  
Author(s):  
Elin Marita Hermundstad ◽  
Jan R. Hoff
Keyword(s):  
Time Domain ◽  
Transfer Functions ◽  
Experimental Results ◽  
Numerical Code ◽  
Ship Motions ◽  
Time Domain Simulation ◽  
Regular Waves ◽  
Simulation Code ◽  
Wigley Hull ◽  
Wave Induced

This paper presents a new unified seakeeping-maneuvering simulation model valid for surface ships and underwater vessels. If the total ship motions are derived from the traditional formulations for the hydrodynamic and maneuvering models, considering them as two separate problems, the results will be inconsistent. It has therefore been necessary to develop a unified formulation which calculates the total ship motions including both the maneuvering aspects and the wave induced motions. Focus in this study has been on submarines. Examples of application of the developed time domain simulation code are given. These are simulations of the response and corresponding control plane forces of a submarine in straight line motions in regular waves at given headings. The developed code can also be used to e.g. simulate turning circles. This has been conducted for the same submarine, and the results are compared to experimental results. Additionally, simulations of the response of a surface vessel (Wigley hull) with forward speed in regular waves at given headings are presented. In this case only the potential forces are considered. The results from the simulations are used to establish motion transfer functions, which are compared to other numerical and experimental results. There are some limitations in the developed method which affects the application area of the numerical code. This refers particularly to underwater vessels. This will be addressed, and further possible development of the method will be discussed.

Nonlinear Dynamics Behavior of Tethered Submerged Buoy under Wave Loadings

2020 ◽  
Vol 21 (1) ◽  
pp. 11-21
Author(s):  
Lin Zhao ◽  
Weihao Meng ◽  
Zhongqiang Zheng ◽  
Zongyu Chang
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamic Behavior ◽  
Coupling Factor ◽  
Dynamic Responses ◽  
Mooring Line ◽  
Second Law ◽  
Largest Lyapunov Exponent ◽  
Nonlinear Characteristic ◽  
Runge Kutta Method ◽  
Marine Engineering

AbstractTethered submerged buoy is used extensively in the field of marine engineering. In this paper considering the effect of wave, the nonlinear dynamics behavior of tethered submerged buoy is debated under wave loadings. According to Newton’s second law, the dynamic of the system is built. The coupling factor of the system is neglected, the natural frequency is calculated. The dynamic responses of the system are analyzed using Runge–Kutta method. Considering the variety of the steepness kA, the phenomenon of dynamic behavior can be periodic, double periodic and quasi-periodic and so on. The bifurcation diagram and the largest Lyapunov exponent are applied to judge the nonlinear characteristic. It is helpful to understand the dynamic behavior of tethered submerged buoy and design the mooring line of tethered submerge buoy.

Numerical investigation of the propagation of shock waves in rigid porous materials: development of the computer code and comparison with experimental results

1996 ◽  
Vol 324 ◽  
pp. 163-179 ◽  
Author(s):  
A. Levy ◽  
G. Ben-Dor ◽  
S. Sorek
Keyword(s):  
Porous Materials ◽  
Initial Conditions ◽  
Computer Code ◽  
Experimental Results ◽  
Numerical Code ◽  
Materials Development ◽  
Numerical Predictions ◽  
Wide Range ◽  
Dimensional Version ◽  
The One

The governing equations of the flow field which is obtained when a thermoelastic rigid porous medium is struck head-one by a shock wave are developed using the multiphase approach. The one-dimensional version of these equations is solved numerically using a TVD-based numerical code. The numerical predictions are compared to experimental results and good to excellent agreements are obtained for different porous materials and a wide range of initial conditions.

Performance and Boundary Layer Development of a High Turning Compressor Cascade at Sub- and Supercritical Flow Conditions

2012 ◽  
Author(s):  
Christoph Bode ◽  
Dragan Kožulović ◽  
Udo Stark ◽  
Heinz Hoheisel
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Density Ratio ◽  
Boundary Layer Separation ◽  
Experimental Results ◽  
Numerical Code ◽  
Compressor Cascade ◽  
Boundary Layer Development ◽  
Boundary Layer Interaction ◽  
Inlet Angle

Based on current numerical investigations, the present paper reports on new Q2D midspan-calculations and results for the well known high turning (Δβ = 50°) supercritical (Ma1 = 0.85) compressor cascade V2. A Q2D treatment of the problem was chosen in order to avoid the difficult modelling of the porous endwalls in a corresponding 3D approach. All simulations were done with the RANS solver TRACE of the DLR Cologne in combination with modified versions of the Wilcox turbulence model and Langtry/Menter transition model. Existing experimental Q2D midspan-results for the V2 compressor cascade were used to demonstrate the improved ability of the numerical code to determine performance characteristics, blade pressure and Mach number distributions as well as boundary layer parameter and velocity distributions. The loss characteristics show minimum loss regions when plotted against inlet angle or axial velocity density ratio. Within these regions, increasing with decreasing Mach number, the experimental results were adequately predicted. Outside these regions it turned out difficult to reproduce the experimental results due to increasing boundary layer separation. Furthermore, the prediction quality was very good for subsonic conditions (Ma1 = 0.60) and still reasonable for supercritical conditions (Ma1 = 0.85), where shock/boundary layer interaction made the prediction more difficult.

Dynamic Analysis of a Floating Offshore Wind Turbine Under Extreme Environmental Conditions

2012 ◽  
Author(s):  
Tomoaki Utsunomiya ◽  
Shigeo Yoshida ◽  
Hiroshi Ookubo ◽  
Iku Sato ◽  
Shigesuke Ishida
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Environmental Conditions ◽  
Aerodynamic Force ◽  
Experimental Results ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Analysis Tool ◽  
Simulation Code ◽  
Floating Offshore Wind Turbine

This paper is concerned with the development of a Floating Offshore Wind Turbine (FOWT) utilizing spar-type floating foundation. In order to design such a structure, it is essential to evaluate the dynamic response under extreme environmental conditions. In this study, therefore, a dynamic analysis tool has been developed. The dynamic analysis tool consists of a multi-body dynamics solver (MSC.Adams), aerodynamic force evaluation library (NREL/AeroDyn), hydrodynamic force evaluation library (In-house program named SparDyn), and mooring force evaluation library (In-house program named Moorsys). In this paper, some details of the developed dynamic analysis tool are given. In order to validate the program, comparison with the experimental results, where the wind, current and wave are applied simultaneously, has been made. The comparison shows that satisfactory agreements between the simulation and the experimental results are obtained. However, when VIM (Vortex Induced Motion) occurs, the current loads and cross flow responses (sway and roll) are underestimated by the simulation since the simulation code does not account for the effect of VIM.

High Holding Power Torpedo Pile: Results for the First Long Term Application

2004 ◽  
Author(s):  
Jairo Bastos de Araujo ◽  
Roge´rio Diniz Machado ◽  
Cipriano Jose de Medeiros Junior
Keyword(s):  
Water Depth ◽  
Deep Water ◽  
Field Tests ◽  
Free Fall ◽  
Mooring System ◽  
Holding Power ◽  
Campos Basin ◽  
Anchoring System ◽  
Very High

Petrobras developed a new kind of anchoring device known as Torpedo. This is a steel pile of appropriate weight and shape that is launched in a free fall procedure to be used as fixed anchoring point by any type of floating unit. There are two Torpedoes, T-43 and T-98 weighing 43 and 98 metric tons respectively. On October 2002 T-43 was tested offshore Brazil in Campos Basin. The successful results approved and certified by Bureau Veritas, and the need for a feasible anchoring system for new Petrobras Units in deep water fields of Campos Basin led to the development of a Torpedo with High Holding Power. Petrobras FPSO P-50, a VLCC that is being converted with a spread-mooring configuration will be installed in Albacora Leste field in the second semester of 2004. Its mooring analysis showed that the required holding power for the mooring system would be very high. Drag embedment anchors option would require four big Anchor Handling Vessels for anchor tensioning operations at 1400 m water depth. For this purpose T-98 was designed and its field tests were completed in April 2003. This paper discusses T-98 design, building, tests and ABS certification for FPSO P-50.

Experiment on the Attenuation Characteristics of Shock Wave Interacting with Open and Closed Foam

2014 ◽  
Vol 1035 ◽  
pp. 445-452
Author(s):  
Jian Wang ◽  
Bao Gui Wang ◽  
Gang Tao
Keyword(s):  
Shock Wave ◽  
Internal Friction ◽  
Dynamic Behavior ◽  
Solid Phase ◽  
Experimental Results ◽  
Reflection And Transmission ◽  
Attenuation Characteristics

For understanding the dynamic behavior of open and closed foam subject to a shock wave, this paper through experiments, to gain a deeper understanding of the incidence, reflection and transmission of a shock wave when it interacted with cellular foam. Moreover, by analyzing the loss of the peak overpressure and positive impulse, we were able to respectively know the positive impulse of the incidence, reflection and transmission shock wave. The experimental results indicated that the attenuation capability for foam to the shock wave was caused by the internal friction and deformation of solid phase, which would absorb the energy of the shock wave. From the results we gain an understanding that the mechanical phenomenon of open foam to shock wave are not fully consistent with those of closed foam , while the attenuation of open foam to shock wave is more effective than that of closed foam.

Telescope Interface Compatibility

1971 ◽  
Vol 11 ◽  
pp. 50-51
Author(s):  
I. G. Van Breda
Keyword(s):  
South Africa ◽  
Cape Town ◽  
International Standards ◽  
General Relevance ◽  
Royal Observatory ◽  
Under Construction ◽  
The University

Recently an automatic UBVRI photometer has been under construction at the University Observatory, St Andrews, for use on the 1.02-metre telescope at the Royal Observatory, Cape Town. Two problems have been encountered which would seem to be of general relevance. Firstly a Cassegrain focus acquisition head, specific to the photometer, was required, and secondly a large rack of electronics must be shipped to South Africa. Clearly these problems have occurred to other guest observers, and it is suggested that they would be greatly reduced by the adoption of international standards, preferably through the IAU, relating to mechanical and electronic interfaces.

Sign in / Sign up

Export Citation Format

Share Document