Parametric study on environmetal loads of hindcast and measured full scale data

2011 ◽  
Author(s):  
Zuraida Mayeetae ◽  
Mohd Shahir Liew ◽  
Kurian V. John
Keyword(s):  
Parametric Study ◽  
Full Scale ◽  
Scale Data

Benchmarking of Truss Spar Vortex Induced Motions Derived From CFD With Experiments

2005 ◽  
Author(s):  
John Halkyard ◽  
Senu Sirnivas ◽  
Samuel Holmes ◽  
Yiannis Constantinides ◽  
Owen H. Oakley ◽  
...  
Keyword(s):  
Scale Up ◽  
Vertical Cylinder ◽  
Reynolds Numbers ◽  
Full Scale ◽  
Scale Model ◽  
Current Direction ◽  
Test Results ◽  
Helical Strakes ◽  
Truss Spar ◽  
Scale Data

Floating spar platforms are widely used in the Gulf of Mexico for oil production. The spar is a bluff, vertical cylinder which is subject to Vortex Induced Motions (VIM) when current velocities exceed a few knots. All spars to date have been constructed with helical strakes to mitigate VIM in order to reduce the loads on the risers and moorings. Model tests have indicated that the effectiveness of these strakes is influenced greatly by details of their design, by appurtenances placed on the outside of the hull and by current direction. At this time there is limited full scale data to validate the model test results and little understanding of the mechanisms at work in strake performance. The authors have been investigating the use of CFD as a means for predicting full scale VIM performance and for facilitating the design of spars for reduced VIM. This paper reports on the results of a study to benchmark the CFD results for a truss spar with a set of model experiments carried out in a towing tank. The focus is on the effect of current direction, reduced velocity and strake pitch on the VIM response. The tests were carried out on a 1:40 scale model of an actual truss spar design, and all computations were carried out at model scale. Future study will consider the effect of external appurtenances on the hull and scale-up to full scale Reynolds’ numbers on the results.

Elimination of viruses, bacteria and protozoan oocysts by slow sand filtration

2004 ◽  
Vol 50 (1) ◽  
pp. 147-154 ◽  
Author(s):  
W.A.M. Hijnen ◽  
J.F. Schijven ◽  
P. Bonné ◽  
A. Visser ◽  
G.J. Medema
Keyword(s):  
Pilot Plant ◽  
Pathogenic Bacteria ◽  
Laboratory Experiments ◽  
Full Scale ◽  
Sand Filters ◽  
E Coli ◽  
Thermotolerant Coliforms ◽  
Filter Bed ◽  
Scale Data ◽  
Bacteria Removal

The decimal elimination capacity (DEC) of slow sand filters (SSF) for viruses, bacteria and oocysts of Cryptosporidium has been assessed from full-scale data and pilot plant and laboratory experiments. DEC for viruses calculated from experimental data with MS2-bacteriophages in the pilot plant filters was 1.5-2 log10. E. coli and thermotolerant coliforms (Coli44) were removed at full-scale and in the pilot plant with 2-3 log10. At full-scale, Campylobacter bacteria removal was 1 log10 more than removal of Coli44, which indicated that Coli44 was a conservative surrogate for these pathogenic bacteria. Laboratory experiments with sand columns showed 2-3 and >5-6 log10 removal of spiked spores of sulphite-reducing clostridia (SSRC; C. perfringens) and oocysts of Cryptosporidium respectively. Consequently, SSRC was not a good surrogate to quantify oocyst removal by SSF. Removal of indigenous SSRC by full-scale filters was less efficient than observed in the laboratory columns, probably due to continuous loading of these filter beds with spores, accumulation and retarded transport. It remains to be investigated if this also applies to oocyst removal by SSF. The results additionally showed that the schmutzdecke and accumulation of (in)organic charged compounds in the sand increased the elimination of microorganisms. Removal of the schmutzdecke reduced DEC for bacteria by ±2 log10, but did not affect removal of phages. This clearly indicated that, besides biological activity, both straining and adsorption were important removal mechanisms in the filter bed for microorganisms larger than viruses.

An Analysis of the Aerodynamic Characteristics of Split Flaps

1940 ◽  
Vol 44 (352) ◽  
pp. 338-349
Author(s):  
A. P. West
Keyword(s):  
Experimental Data ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
The Other ◽  
Aircraft Industry ◽  
The Past ◽  
The Many ◽  
Lift And Drag ◽  
Scale Data

During the past few years an extensive amount of experimental data on split flaps has been made available to the aircraft industry, through the publications of aeronautical research laboratories, both in this country and abroad. In general, each publication deals with one particular aspect of the problem, and when the effect of wing flaps on the performance of an aircraft is being estimated a certain amount of difficulty may be experienced in deciding which of the many reports available gives results most readily applicable to the case being considered ; and what allowances, if any, should be made for wing taper, flap cut-out, fuselage, etc.In this report the available data has been analysed with a view to answering these questions, and presented in such a form that it may be readily applied to determine the most probable change in the aerodynamic characteristics of a wing that may be expected from the use of this type of flap.From the appendix an estimate of the accuracy of the method can be obtained, as a comparison with full-scale data is given for lift and drag, and for the other flap characteristics the original curves have been reproduced.

Determination of textile dyeing wastewater COD components by comparison with respirometry and full‐scale data

2010 ◽  
Vol 31 (11) ◽  
pp. 1191-1201 ◽  
Author(s):  
Jing‐Jie Yu ◽  
Guo‐Wei Gu ◽  
Giovanni Esposito ◽  
Massimiliano Fabbricino ◽  
Shao‐Po Wang ◽  
...  
Keyword(s):  
Full Scale ◽  
Dyeing Wastewater ◽  
Textile Dyeing ◽  
Scale Data ◽  
Textile Dyeing Wastewater

Prediction of First-Order Vessel Responses with Applications to Decision Support Systems

2015 ◽  
Author(s):  
Ulrik D. Nielsen ◽  
Toshio Iseki
Keyword(s):  
Decision Support ◽  
Decision Support Systems ◽  
Support Systems ◽  
Simple Approach ◽  
Full Scale ◽  
Uncertainty Measure ◽  
First Order ◽  
Future Developments ◽  
Vessel Response ◽  
Scale Data

The paper presents a practical and simple approach for making vessel response predictions. Features of the procedure include a) predictions which are scaled so to better agree with corresponding true, future values to be measured at the time the predictions apply at; and b) predictions that are assigned an uncertainty measure to reflect a level of confidence. The approach is tested with full-scale data and the obtained results/predictions agree well with measured values. Potentially, the procedure is therefore very useful in future developments of general decision support systems.

LOCAL STUDIES OF ICE COVER EFFECTS ON DAM GATES

2021 ◽  
Vol 11 (2) ◽  
pp. 62-66
Author(s):  
Sergey V. EVDOKIMOV ◽  
Alexey A. ROMANOV ◽  
Boris G. IVANOV
Keyword(s):  
Power Plants ◽  
Practical Interest ◽  
Full Scale ◽  
Hydroelectric Power Station ◽  
Hydroelectric Power ◽  
Power Stations ◽  
Operation Rules ◽  
Static Operation ◽  
Technical Operation ◽  
Scale Data

The experience of operation of surface emergency gates in ice-breaking conditions at a number of hydroelectric power plants has shown the insuffi cient eff ectiveness of the methods used to combat freezing of structures. The rules for technical operation of spillway dam gates in winter provide for heating of structures by slots, threshold and skin in conjunction with measures to maintain mines before construction. However, measures to heat gates and build mines are not always suffi ciently justifi ed and justifi ed. In order to obtain full-scale data and scientifi c information for the development of recommendations on operating and accounting modes during design, full-scale studies of stresses and defl ections in the load-bearing elements of the watershed gate of the hydroelectric power station were carried out. This article presents the results of fi eld studies in comparison with calculated values. As a result of the studies, information on the static operation of fl at gates in winter conditions is obtained, which is of theoretical and practical interest. The materials can be used to clarify technical operation rules and to clarify regulatory documents for the design of hydromechanical equipment at hydroelectric power stations.

A Novel Data Processing Method for Ice Pressure Statistics

2015 ◽  
Author(s):  
Karoline M. Neumann ◽  
Sören Ehlers ◽  
Bernt J. Leira ◽  
Pentti Kujala
Keyword(s):  
Data Processing ◽  
Design Parameter ◽  
Processing Method ◽  
Full Scale ◽  
Cumulative Distribution ◽  
Discrete Events ◽  
Data Processing Method ◽  
Ice Loads ◽  
Ice Pressure ◽  
Scale Data

Maritime activities in ice bound areas increase demand for design of structures to withstand ice loads. A cumulative distribution with parameter α as a function of area is published in ISO19906 [1], based on analysis of multiple different discrete full scale rams from Jordaan [2] for application on design loads of discrete impacts. Taylor [3] performs a reanalysis including more full scale data, and taking into account the effect of exposure, presents design parameter curves α-area and x0-area. These are valuable, but are to be applied for design of discrete events, and can only be obtained from discrete event data. The objective of this paper is to describe and demonstrate a data processing method based on semi-continuous ice pressure data that can be applied not only for discrete events, but also for semi-continuous interaction. A finely meshed tactile sensor is applied. Jordaan’s [2] max event method is applied on a new definition of event, based on triggered sensels that are adjacent in time and space. The method is demonstrated on a model scale data set from Aalto University, and example design parameter curves are presented. Applying the developed method on full scale data, the results can be valuable for design of semi-continuous ice loads.

Validation of Sleeve Weld Integrity and Workmanship Level Development

2006 ◽  
Author(s):  
Robert Lazor ◽  
Brock Bolton ◽  
Aaron Dinovitzer
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Full Scale ◽  
Loading Conditions ◽  
Element Analysis ◽  
Service Failures ◽  
Applied Loading ◽  
Fea Modeling ◽  
Field And Laboratory Conditions ◽  
Scale Data

Full encirclement repair sleeves with fillet-welded ends are often used as permanent repairs on pipelines to reinforce areas with defects, such as cracks or corrosion. In-service failures have occurred at reinforcing sleeves as a result of defects associated with the sleeve welds, such as hydrogen-induced cracks and undercut at the fillet welds, inadequate weld size, and sleeve longitudinal seam ruptures. This work was undertaken to support the development of tools for sleeve design and for conducting an engineering assessment to determine the tolerable dimensions of flaw indications at full encirclement repair sleeves. In particular, the project was intended to validate the stresses estimated using finite element analysis (FEA) models against actual in-service loading conditions experienced at reinforcing sleeves. The experimental work focused on the collection of full-scale experimental data describing pipe and sleeve strains for the following field and laboratory conditions: • Strains induced by sleeve welding, • Strains induced by pressurization of the sleeved pipe, • Strains induced by pressurization of the sleeved pipe and the annulus between the pipe and sleeve. Finite element models of the field and laboratory sleeved pipe segments were developed and subjected to the same applied loading conditions as the full-scale sleeved pipe segments. Comparisons of the measured strains against those estimated using FEA were completed to determine the ability of the models to predict the behaviour of the sleeved pipe segments. Comparisons were made to illustrate the relative strain levels and deformation trends, the accuracies of the strain predictions and trends in changes with pressure, the differences in behaviours between tight and loose fitting sleeves, and the effects of pressurizing the annulus between the pipe wall and sleeve. The analysis of the field data and FEA modeling predictions led to several conclusions regarding to use of numerical models for predicting sleeved pipe behaviour and weld flaw acceptance: • FEA results demonstrated behaviours that were consistent with full scale data, • Trends in the FEA predicted strains agreed with the full-scale data, • FEA models describing the effects of gaps between the pipe and sleeve and annulus pressurization agreed with field experience and engineering judgment, • Evaluation of the significance of root and toe flaws can be completed by extending the models validated in this work.

Iceberg/Seabed Interaction Events Observed During the DIGS Experiment

1991 ◽  
Vol 113 (1) ◽  
pp. 74-87 ◽  
Author(s):  
J. H. Lever ◽  
D. W. Bass ◽  
C. F. M. Lewis ◽  
K. Klein ◽  
D. Diemand ◽  
...  
Keyword(s):  
Full Scale ◽  
Labrador Sea ◽  
Data Sets ◽  
Side Scan Sonar ◽  
Time Stepping ◽  
Dynamic Events ◽  
New Information ◽  
Stability Maps ◽  
Seabed Interaction ◽  
Scale Data

The Dynamics of Iceberg Grounding and Scouring (DIGS) experiment was conducted in the Labrador Sea during August 1985. The objectives of the experiment were to obtain full-scale data sets documenting iceberg/seabed interactions, and to obtain by direct observation new information regarding the processes of iceberg scour formation and degradation. Utilizing a vessel and a helicopter, measurements were made of icebergs’ above and below-water shapes, plus local winds, waves, currents and tides. Special self-contained motion monitoring packages were deployed by helicopter on icebergs thought to be good grounding candidates. Seabed observations were made directly using the submersible Pisces IV, and extensive side-scan sonar data were collected. This paper describes two dynamic iceberg/seabed interaction events documented during DIGS: the roll/pitting behavior of the 1.2-million-ton domed iceberg “Bertha,” and the split/grounding behavior of the 7.7-million-ton tabular iceberg “Gladys.” This latter event is particularly interesting due to its very energetic nature, and the fact that it represents the only full-scale observation of any iceberg impact with sufficient documentation to yield estimates of the interaction forces. Subsequent to the experiment, the recorded above and below-water shapes were used to obtain hydrostatic stability maps for these icebergs. A time stepping procedure was also developed to re-create these two dynamic events, and comparisons between the observed and simulated motions are provided in this paper.

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