Preliminary model tests for the design of a gliding deep water elevator

2007 ◽  
Author(s):  
Chris Roman ◽  
Todd Gregory ◽  
Eric Martin ◽  
Alex Sanguinetti ◽  
Jenna Drummond
Keyword(s):  
Deep Water ◽  
Model Tests ◽  
Preliminary Model

Resistance Tests of an Articulated Pusher Barge System in Deep and Shallow Water

2021 ◽  
Author(s):  
Li Zhang ◽  
Lei Xing ◽  
Mingyu Dong ◽  
Weimin Chen
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Deep Water ◽  
Water Resistance ◽  
Model Tests ◽  
System 2 ◽  
Changing Trend ◽  
The Difference ◽  
Transport Vessel ◽  
Resistance Performance

Abstract Articulated pusher barge vessel is a short-distance transport vessel with good economic performance and practicability, which is widely used in the Yangtze River of China. In this present work, the resistance performance of articulated pusher barge vessel in deep water and shallow water was studied by model tests in the towing tank and basin of Shanghai Ship and Shipping Research Institute. During the experimental investigation, the articulated pusher barge vessel was divided into three parts: the pusher, the barge and the articulated pusher barge system. Firstly, the deep water resistance performance of the articulated pusher barge system, barge and the pusher at design draught T was studied, then the water depth h was adjusted, and the shallow water resistance at h/T = 2.0, 1.5 and 1.2 was tested and studied respectively, and the difference between deep water resistance and shallow water resistance at design draught were compared. The results of model tests and analysis show that: 1) in the study of deep water resistance, the total resistance of the barge was larger than that of the articulated pusher barge system. 2) for the barge, the shallow water resistance increases about 0.4–0.7 times at h/T = 2.0, 0.5–1.1 times at h/T = 1.5, and 0.7–2.3 times at h/T = 1.2. 3) for the pusher, the shallow water resistance increases about 1.0–0.4 times at h/T = 2.7, 1.2–0.9 times at h/T = 2.0, and 1.7–2.4 times at h/T = 1.6. 4) for the articulated pusher barge system, the shallow water resistance increases about 0.2–0.3 times at h/T = 2.0, 0.5–1.3 times at h/T = 1.5, and 1.0–3.5 times at h/T = 1.2. Furthermore, the water depth Froude number Frh in shallow water was compared with the changing trend of resistance in shallow water.

scholarly journals Modelling the embedment process during offshore pipe-laying on fine-grained soils

2013 ◽  
Vol 50 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Z.J. Westgate ◽  
D.J. White ◽  
M.F. Randolph
Keyword(s):  
Deep Water ◽  
Small Amplitude ◽  
Model Tests ◽  
Soil Parameters ◽  
Sea State ◽  
Field Surveys ◽  
Centrifuge Model ◽  
Fine Grained ◽  
Displacement Patterns ◽  
Centrifuge Model Tests

Subsea pipelines are becoming an increasingly significant element of offshore hydrocarbon developments as exploration moves into deep-water environments further from shore. During the lay process, pipelines are subject to small amplitude vertical and horizontal oscillations, driven by the sea state and lay vessel motions. Centrifuge model tests have been used to simulate these small-amplitude lay effects, with varying degrees of idealization relative to the real lay process. In the soft soils found in deep water, pipe embedment can exceed a diameter or more, thus significantly affecting the lateral pipe–soil interaction, axial resistance, and thermal insulation. In this paper, results from centrifuge model tests are used to calibrate a model for calculating the dynamic embedment of a subsea pipeline. The model uses elements of plasticity theory to capture the effects of combined vertical and horizontal loading, and incorporates the softening of the surrounding soil as it is remoulded due to the pipeline motions. Influences from the lay rate, lay geometry, and sea state are included in the calculation process. The model is compared with observed as-laid pipeline embedment data from field surveys at three different offshore sites. Using site-specific soil parameters obtained from in situ testing and idealized pipe loads and motions to represent the load and displacement patterns during offshore pipe-laying, respectively, the model is shown to capture well the final as-laid embedment measured in the field surveys.

Development of Deep Water Multicolumn Buoy

2014 ◽  
Author(s):  
Rodrigo A. Barreira ◽  
Vinicius L. Vileti ◽  
Joel S. Sales ◽  
Sergio H. Sphaier ◽  
Paulo de Tarso T. Esperança
Keyword(s):  
Conceptual Design ◽  
Water Depth ◽  
Deep Water ◽  
Model Tests ◽  
Optimization Process ◽  
Life Duration

A new conceptual design of a deepwater MONOBUOY, named DeepWater MultiColumn Buoy (DWMCB), patent PCT/BR2011/000133, was developed by PETROBRAS/CENPES. The DWMCB was designed to be part of an offloading system for a Spread Moored Floating Production Offloading Unit (FPSO). The offloading system principle consists of Oil being exported from the FPSO to a Shutle tanker passing through Offloading Oil Lines (OOLs) that are supported by the DWMCB. The system is designed to operate at a water depth of 2,200 meters, with expected in site life duration of 25 years. The geometry of DWMCB was defined after an optimization process in order to minimize its motions. This paper describes the development of this concept and discusses the results from some design verifications done with the help of a model tests campaign. An equivalent traditional shaped monobuoy was also tested for comparison purposes.

Experimental Assessment of the Offshore Launching Operation of a Jack-Up Unit

2014 ◽  
Author(s):  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança ◽  
Mário Moura ◽  
Jacques Raigorodsky
Keyword(s):  
Experimental Approach ◽  
Experimental Tests ◽  
Model Tests ◽  
Experimental Assessment ◽  
Simulation Tools ◽  
Experimental Campaign ◽  
Preliminary Model ◽  
Stage 4 ◽  
Reaction Forces ◽  
Jack Up

Recently, an experimental campaign was carried out to assess the feasibility of the launching operation of two jack-up units using a barge as the launching platform. This experimental study was divided in four stages. In stages 1 to 3, a series of preliminary model tests were performed in order to provide scientific understanding of the mechanics of the operation, and investigate systematically the influence of launching parameters. The experimental approach developed for testing this operation and the results of the preliminary launching tests have been discussed in detail in a previous paper [1]. Based on the analyses of the experimental results of stages 1 to 3 and, the results of numerical simulation tools, in stage 4, a final launching condition was designed and a new set of model tests were specified to check the safety of the operation. This paper presents the results and analyses of the experimental tests in stage 4. The conditions tested in this stage covered the expected real launching condition and possible deviations in some launch parameters. The tests results include the 6-DOF motions and trajectories of the launched jack-up and the launch barge, and the reaction forces on the barge rocker arms. Later on, the success of the launching operations of P-59 and P-60 jack-up units confirmed the experimental investigation results and the feasibility of this novel launching procedure. Furthermore, it can be concluded that the experimental approach efficiently served as a tool for the assessment of high risk operations.

Model Tests and Time-Domain Coupled Analysis of a Dicas-Moored FPSO in Deep Water

2003 ◽  
Author(s):  
Rolf Baarholm ◽  
Carl Trygve Stansberg ◽  
Fabio Gondim Palazzo
Keyword(s):  
Deep Water ◽  
Time Domain ◽  
Model Tests ◽  
Coupled Analysis

Experimental Determination of Resonant Response in the Narrow Gap Between Two Side-by-Side Fixed Bodies in Deep Water

2016 ◽  
Author(s):  
Wenhua Zhao ◽  
Hugh Wolgamot ◽  
Scott Draper ◽  
Paul H. Taylor ◽  
Rodney Eatock Taylor ◽  
...  
Keyword(s):  
White Noise ◽  
Numerical Simulations ◽  
Water Depth ◽  
Deep Water ◽  
Model Tests ◽  
Full Scale ◽  
Resonance Phenomenon ◽  
Resonant Response ◽  
Gap Resonance ◽  
Wave Basin

Floating liquefied natural gas (FLNG) facilities are a new type of offshore structure, which have been developed as a game changer in offshore hydrocarbon development for unlocking stranded gas reserves. One of the key challenges associated is offloading from FLNG facilities to LNG carriers. Offloading may proceed with vessels in a side-by-side configuration, which allows offtake by un-modified vessels and minimizes requirements for new hardware or procedures (e.g. compared to a tandem operation). Significant challenges remain, however, and reliable offloading is critical for successful FLNG implementation. In this scenario, the two vessels are separated by a narrow 4 m wide gap. The resonant response of the sea surface in the gap has been predicted by numerical simulations [1] to be a few times that of the incident waves at particular frequencies. As a consequence, the gap resonant response may play a role in determining the operational window for side-by-side offloading operations, and thus has attracted a lot of attention recently. There have been studies on this topic both numerically and experimentally. However, many of these studies are in 2 dimensions (2D), for relatively large gaps and relatively shallow water depth, which may pose difficulties when extending the results to a real project. It is unclear what will happen for a gap resonance if the gap width gets narrower (say 4 m in full scale) and the water depth gets deeper (say 600 m in full scale). In this study, we conducted a series of model tests at a scale of 1:60 in a large wave basin, and focused on deep water and, crucially, narrow gaps, which are closer to a real project geometry. To facilitate future numerical simulations, we used two identical fixed bodies in the model tests and the vessels were simple barge-like shapes. Using white noise waves as the excitation, which covers a broad brand, the response of the fluid in the gap has been measured at several points. In these experiments, different modes of the gap resonance have been observed. Response amplitude operators (RAOs) of the gap resonance have been obtained through spectral analyses, which provide valuable information for the design of side-by-side operations and will benefit future numerical simulations. Test runs in white noise waves with different significant wave heights were also performed, to study the nonlinearities of the gap resonance phenomenon.

Assessment of a Jack-Up Offshore Launching Through Model Tests and Field Measurements

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança ◽  
Mário Moura ◽  
Jacques Raigorodsky
Keyword(s):  
Experimental Approach ◽  
Field Measurements ◽  
Experimental Tests ◽  
Model Tests ◽  
Efficient Tool ◽  
Simulation Tools ◽  
Preliminary Model ◽  
Stage 4 ◽  
Reaction Forces ◽  
Jack Up

Recently, an experimental campaign was carried out to assess the feasibility of the launching operation of two jack-up units using a barge as the launching platform. This experimental study was divided in four stages. In stages 1 to 3, a series of preliminary model tests were performed in order to provide scientific understanding of the mechanics of the operation and investigate systematically the influence of launching parameters. The experimental approach developed for testing this operation and the results of the preliminary launching tests have already been discussed in detail. Based on the analyses of the experimental results of stages 1 to 3 and the results of numerical simulation tools in stage 4, a final launching condition was designed and a new set of model tests was specified to check the safety of the operation. This paper presents the results and analyses of the experimental tests of stage 4. The conditions tested in this stage covered the expected real launching condition and possible deviations in some launch parameters. The tests results include the 6 degree-of-freedom (DOF) motions and trajectories of the launched jack-up and the launch barge, and the reaction forces on the barge rocker arms. Later on, the success of the launching operations of P-59 and P-60 jack-up units confirmed the experimental investigation results and the feasibility of this novel launching procedure. During the launching of unit P-60, field measurements were performed that confirmed that model tests as an efficient tool for the assessment of high risk operations.

scholarly journals DETERMINATION OF THE WAVE HEIGHT IN NATURE FROM MODEL TESTS SUPPLEMENTED BY CALCULATION

2011 ◽  
Vol 1 (6) ◽  
pp. 12
Author(s):  
J. G.H.R. Diephuis ◽  
J. G. Gerritze
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Deep Water ◽  
Bottom Topography ◽  
Model Tests ◽  
Small Scale ◽  
Wave Characteristics ◽  
Sea Bottom ◽  
The Waves

This paper deals with the problem of determining the wave characteristics in shallow water from those in deep water. In general this can be done by means of a refraction calculation. If the sea bottom topography is too irregular the height of the waves can be determined by means of a small-scale refraction model. In both cases, however, some additional effects have to be taken into account, viz. the influence of the bottom friction and the influence of the wind.

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