Performance of a Covering Pipe for the Protection of Underwater Cable Subjected to on-Site Impact Loadings

2011 ◽  
Vol 82 ◽  
pp. 810-815
Author(s):  
Hsien Hua Lee
Keyword(s):  
Cast Iron ◽  
Water Depth ◽  
Deep Water ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Full Scale ◽  
Scale Model ◽  
Local Power ◽  
Pipe System ◽  
Power Company

In this study, a protection-pipe system has been developed for the protection of undersea electricity cable layout along shoreline with medium deep water. The protection pipes are made of cast-iron alloys while the dimensions are designed corresponding to the balk diameter of electricity cables. The water depth of the area with cable layout is ranged from several meters to a hundred meters, where berthing anchoring from commercial ships and towing operation from fishing boats are constantly found. Therefore, to make sure that the protection pipe can work dependably against the loadings mainly from the operation as was mentioned, both analytical analysis and experimental tests were carried out. In the experimental studies, the full-scale model of several sets of protection-pipe system was tested for impact loadings. It was found from the results of both the analysis and experimental tests that the protection-pipes are able to meet the requirements of the local power company TPC set for the cable layout under seawater.

Wave Effects on the Turning Ability of an Ultra Large Container Ship in Shallow Water

2019 ◽  
Author(s):  
Manases Tello Ruiz ◽  
Marc Mansuy ◽  
Luca Donatini ◽  
Jose Villagomez ◽  
Guillaume Delefortrie ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Experimental Studies ◽  
Scale Model ◽  
Confined Water ◽  
The North ◽  
Calm Water ◽  
Wave Effects ◽  
Water Effects ◽  
Large Container

Abstract The influence of waves on ship behaviour can lead to hazardous scenarios which put at risk the ship, the crew and the surroundings. For this reason, investigating the effect of waves on manoeuvring is of relevant interest. Waves may impair the overall manoeuvring performance of ships hence increasing risks such as collisions, which are of critical importance when considering dense traffic around harbour entrances and in unsheltered access channels. These are conditions met by Ultra Large Container Ships (ULCS) when approaching a port, e.g. in the North Sea access channels to the main sea ports of Belgium. Note that due to the large draft of ULCS and the limited water depth, shallow water effects will also influenced the ship. Thus, in such scenarios the combined effects of shallow water and waves on the ship’s manoeuvring need to be studied. The present work investigates the effect of waves on the turning ability of an ULCS in shallow water. Simulations are carried out using the two time scale approach. The restricted water depth corresponds to 50% Under Keel Clearance (UKC). To gain a better insight on the forces acting on the ship, the propulsion, and the rudder behaviour in waves experimental studies were conducted. These tests were carried out in the Towing Tank for Manoeuvres in Confined Water at Flanders Hydraulics Research (in co-operation with Ghent University) with a scale model of an ULCS. Different wave lengths, wave amplitudes, ships speeds, propeller rates, and rudder angles were tested. The turning ability characteristics obtained from simulations in waves and calm water are presented, and discussed.

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.

Methodological approach for the optimization of drinking water treatment plants' operation: a case study

2014 ◽  
Vol 71 (4) ◽  
pp. 597-604 ◽  
Author(s):  
Sabrina Sorlini ◽  
Maria Cristina Collivignarelli ◽  
Federico Castagnola ◽  
Barbara Marianna Crotti ◽  
Massimo Raboni
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Distribution System ◽  
Methodological Approach ◽  
Experimental Studies ◽  
Drinking Water Treatment ◽  
Experimental Tests ◽  
Full Scale ◽  
Water Quality Control ◽  
Water Treatment Plants

Critical barriers to safe and secure drinking water may include sources (e.g. groundwater contamination), treatments (e.g. treatment plants not properly operating) and/or contamination within the distribution system (infrastructure not properly maintained). The performance assessment of these systems, based on monitoring, process parameter control and experimental tests, is a viable tool for the process optimization and water quality control. The aim of this study was to define a procedure for evaluating the performance of full-scale drinking water treatment plants (DWTPs) and for defining optimal solutions for plant upgrading in order to optimize operation. The protocol is composed of four main phases (routine and intensive monitoring programmes – Phases 1 and 2; experimental studies – Phase 3; plant upgrade and optimization – Phase 4). The protocol suggested in this study was tested in a full-scale DWTP placed in the North of Italy (Mortara, Pavia). The results outline some critical aspects of the plant operation and permit the identification of feasible solutions for the DWTP upgrading in order to optimize water treatment operation.

Correlation of Prototype and Model-Scale Wave Wake Characteristics of a Catamaran

2009 ◽  
Vol 46 (01) ◽  
pp. 1-15
Author(s):  
Gregor J. Macfarlane
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Water Depth ◽  
Correlation Factor ◽  
Scale Height ◽  
Full Scale ◽  
Scale Model ◽  
Model Scale ◽  
Speed Range ◽  
Scale Data

This paper summarizes an experimental investigation into the correlation of model-scale wave wake measurements against full-scale trial results for a 24-meter long catamaran operating over a range of length Froude numbers. Both full-scale and 1/15th-scale model experiments were conducted over the range of length Froude numbers of approximately 0.3 to 1.0 (full-scale speed range of 6 to 28 knots). The water depth during the experiments was approximately 12 meters, with corresponding depth Froude numbers ranging from subcritical (~0.3), through a transcritical range (~0.8 to 1.1) into low supercritical speeds (up to ~1.3). The results of the investigation confirm that a correlation factor of close to unity be applied when using model-scale experimental data to predict the full-scale height and period of the maximum wave generated by similar catamarans operating within such speed ranges. Consequently, it is expected that the energy of the maximum waves can also be accurately predicted from model-scale data. This paper also provides useful guidance notes for the conduct of full-scale wave wake experiments and highlights some issues regarding the identification of the maximum wave(s) generated when vessels operate at trans and/or supercritical depth Froude numbers.

PSI Armour Wire for High Collapse Performance of Flexible Pipe

2011 ◽  
Author(s):  
Laurent Paumier ◽  
Olivier Mesnage
Keyword(s):  
Water Depth ◽  
Deep Water ◽  
Production Systems ◽  
Dynamic Test ◽  
Full Scale ◽  
Flexible Pipe ◽  
Collapse Resistance ◽  
Potential Applications ◽  
Industrial Procurement ◽  
Tension Capacity

Ultra Deep Water (UDW) developments are now a reality with several fields below 2 000 m water depth now ready for production. Within the domain of flexible pipe technology for UDW, Technip identified a number of technical challenges such as flow assurance, riser tension capacity and hydrostatic collapse resistance. These challenges have been addressed through the qualification of various flexible pipe products/components and riser configurations. This paper will focus on one of the solutions developed which addresses the hydrostatic collapse resistance of the pipe, namely the dynamic PSI wire. The dynamic PSI wire was developed primarily as structurally optimized pressure armour. Based on the efficient structural cross section of the I-beam, the dynamic PSI wire provides a weight/strength optimized configuration for internal pressure capacity of the pipe. It also provides increased crushing strength for installation of the pipe in Ultra Deep Water and significantly increases the hydrostatic collapse resistance of the pipe. The objective of the development of the dynamic PSI wire was to propose a 12″ riser for 2 500 m water depth and smaller diameter down to 3 000 m. This objective has been reached, without impacting the dynamic and sour service capacity of the riser. The dynamic PSI wire has succeeded all the qualification process (industrial procurement & manufacturing, full scale dynamic test, full scale collapse tests, full scale offshore installation test down to 3 000m water depth, NACE test, etc) and is now deemed fully qualified for project application. This paper will present the qualification program and also some field case studies showing the potential applications of flexible risers integrating this new design. The availability of dynamic PSI wires provides operators with the opportunity to develop flexible riser production systems in UDW fields with larger diameters and therefore enhance the subsea production and export systems.

Effect of mesh on CFD aerodynamic performances of a container ship

2020 ◽  
Vol 20 (3) ◽  
pp. 343-353
Author(s):  
Ngo Van He ◽  
Le Thi Thai
Keyword(s):  
Water Surface ◽  
Reference Model ◽  
Full Scale ◽  
Scale Model ◽  
Container Ship ◽  
Ansys Fluent ◽  
Remarkable Effect ◽  
Aerodynamic Performances ◽  
Mesh Convergence

In this paper, a commercial CFD code, ANSYS-Fluent has been used to investigate the effect of mesh number generated in the computed domain on the CFD aerodynamic performances of a container ship. A full-scale model of the 1200TEU container ship has been chosen as a reference model in the computation. Five different mesh numbers for the same dimension domain have been used and the CFD aerodynamic performances of the above water surface hull of the ship have been shown. The obtained CFD results show a remarkable effect of mesh number on aerodynamic performances of the ship and the mesh convergence has been found. The study is an evidence to prove that the mesh number has affected the CFD results in general and the accuracy of the CFD aerodynamic performances in particular.

Computational and experimental studies of the strength of full-scale samples of pipes with defects "metal loss" and "dent with groove"

2020 ◽  
Vol 10 (3) ◽  
pp. 226-233
Author(s):  
Dmitry A. Neganov ◽  
◽  
Victor M. Varshitsky ◽  
Andrey A. Belkin ◽  
◽  
...  
Keyword(s):  
Internal Pressure ◽  
Experimental Studies ◽  
Full Scale ◽  
The Other ◽  
Metal Loss ◽  
Calculation Methods ◽  
Reliable Operation ◽  
Sufficient Stability ◽  
Comparative Results ◽  
The Moment

The article contains the comparative results of the experimental and calculated research of the strength of a pipeline with such defects as “metal loss” and “dent with groove”. Two coils with diameter of 820 mm and the thickness of 9 mm of 19G steel were used for full-scale pipe sample production. One of the coils was intentionally damaged by machining, which resulted in “metal loss” defect, the other one was dented (by press machine) and got groove mark (by chisel). The testing of pipe samples was performed by applying static internal pressure to the moment of collapse. The calculation of deterioration pressure was carried out with the use of national and foreign methodical approaches. The calculated values of collapsing pressure for the pipe with loss of metal mainly coincided with the calculation experiment results based on Russian method and ASME B31G. In case of pipe with dent and groove the calculated value of collapsing pressure demonstrated greater coincidence with Russian method and to a lesser extent with API 579/ASME FFS-1. In whole, all calculation methods demonstrate sufficient stability of results, which provides reliable operation of pipelines with defects.

Experimental Studies Concerning the Semipermeable Membrane Separation Efficiency for 134Cs, 137Cs, 57Co, 58Co, 60Co, 54Mn in Liquid Radioactive Waste I. Treatment of secondary waste from POD decontamination procedure

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Mirela Dulama ◽  
Nicoleta Deneanu ◽  
Cristian Dulama ◽  
Margarit Pavelescu
Keyword(s):  
Membrane Separation ◽  
Separation Efficiency ◽  
Liquid Radioactive Waste ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Suspended Solid ◽  
Process Efficiency ◽  
Active Charcoal ◽  
Precipitation Process ◽  
Pre Treatment

The paper presents the experimental tests concerning the treatment by membrane techniques of radioactive aqueous waste. Solutions, which have been treated by using the bench-scale installation, were radioactive simulated secondary wastes from the decontamination process with modified POD. Generally, an increasing of the retention is observed for most of the contaminants in the reverse osmosis experiments with pre-treatment steps. The main reason for taking a chemical treatment approach was to selectively remove soluble contaminants from the waste. In the optimization part of the precipitation step, several precipitation processes were compared. Based on this comparison, mixed [Fe(CN)6]4-/Al3+/Fe2+ was selected as a precipitation process applicable for precipitation of radionuclides and flocculation of suspended solid. Increased efficiencies for cesium radionuclides removal were obtained in natural zeolite adsorption pre-treatment stages and this was due to the fact that volcanic tuff used has a special affinity for this element. Usually, the addition of powdered active charcoal serves as an advanced purifying method used to remove organic compounds and residual radionuclides; thus by analyzing the experimental data (for POD wastes) one can observe a decreasing of about 50% for cobalt isotopes subsequently to the active charcoal adsorption.. The semipermeable membranes were used, which were prepared by the researchers from the Research Center for Macromolecular Materials and Membranes, Bucharest. The process efficiency was monitored by gamma spectrometry.

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