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Статті в журналах з теми "Speed limits Australia"
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Karndacharuk, Auttapone, and David McTiernan. "Implementation Principles for 30 km/h Speed Limits and Zones." Journal of the Australasian College of Road Safety 30, no. 2 (May 24, 2019): 45–54. http://dx.doi.org/10.33492/jacrs-d-18-00065.
Повний текст джерелаАнотація:
In the context of the Safe System approach for harm minimisation where fatal and serious injuries are not accepted as inevitable costs of mobility in any transport system, there is an increasing need to consider implementing speed limits within the biological tolerance of road users. The need to implement speed limits lower than 40 km/h in an urban area with high pedestrian movement and activity has been recognised by an Australian state road agency. Through a literature review, stakeholder consultation with road transport agencies in Australia and New Zealand and a Safe System analysis, this paper presents the development of guiding principles in implementing 30 km/h speed limits and zones in Australasia. The implementation principles have been developed to inform a revision of the existing speed zoning guidelines and its applications within the jurisdiction, which are also applicable elsewhere across Australasia and internationally.
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WOOLLEY, J. E., R. ZITO, C. B. DYSON, B. STAZIC, and M. A. P. TAYLOR. "IMPACTS OF LOWER SPEED LIMITS IN SOUTH AUSTRALIA." IATSS Research 26, no. 2 (2002): 6–17. http://dx.doi.org/10.1016/s0386-1112(14)60038-8.
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Fildes, Brian, Brendan Lawrence, and Jennifer Oxley. "Low speed limits in residential areas in Melbourne, Australia." Traffic Injury Prevention 20, sup2 (November 1, 2019): S155—S157. http://dx.doi.org/10.1080/15389588.2019.1661678.
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Lahausse, Julie A., Nicole van Nes, Brian N. Fildes, and Michael D. Keall. "Attitudes towards current and lowered speed limits in Australia." Accident Analysis & Prevention 42, no. 6 (November 2010): 2108–16. http://dx.doi.org/10.1016/j.aap.2010.06.024.
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Maklad, Yasser. "Optimistic / Normal / Pessimistic Limits of Urban Wind Speed in Armidale NSW, Australia." IOSR Journal of Engineering 4, no. 11 (2014): 22–47. http://dx.doi.org/10.9790/3021-041112247.
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Shima, Amy L., David S. Gillieson, Gabriel M. Crowley, Ross G. Dwyer, and Lee Berger. "Factors affecting the mortality of Lumholtz's tree-kangaroo (Dendrolagus lumholtzi) by vehicle strike." Wildlife Research 45, no. 6 (2018): 559. http://dx.doi.org/10.1071/wr17143.
Повний текст джерелаАнотація:
Context Vehicle strike is a major issue where wildlife habitat is intersected by busy roads. Near Threatened Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) is a large (5–10 kg) semi-arboreal mammal found in populated rural and forested areas of north-eastern Australia. Warning signs, rope bridges and underpasses have not prevented ~20 animals being killed on the road each year. Aims To identify factors influencing Lumholtz’s tree-kangaroo vehicle strike to help inform mitigation options. Methods Citizen sightings (1998–2000) and 90 road-kills collected over 4.5 years on the Atherton Tablelands, Australia, were examined to determine the causes of vehicle strike in Lumholtz’s tree-kangaroo. The spatial distributions of sightings and road-kills were characterised using nearest-neighbour analysis, and the relationship between them was determined using a Bayesian approach that accounted for spatial autocorrelation. Gender, age, weight, season, rainfall, road and verge characteristics, traffic volumes, speed limits and mitigation measures were recorded to assess their influence on road-kill risk. Adequacy of speed limits to prevent collisions along road sections with more than four road-kills per 8 km (hazard zones) was assessed from visibility and stopping distances. Key results Vehicle strikes mainly affected male tree-kangaroos (2–5 years, 5.5–8 kg), occurred where live animals were most frequently sighted and were most likely on roads with narrow verges, low visibility and medium traffic volumes. Speed limits at hazard zones were inadequate to prevent collisions. Few warning signs corresponded with these zones, and road mortalities persisted where they did. Conclusions Unpredictable dispersal of young males and vehicle speeds unsuited to road conditions drive road mortalities in Lumholtz’s tree-kangaroo. Because tree-kangaroos do not appear to respond to existing mitigation measures, reducing traffic speeds, and increasing visibility, appear to be the most effective mitigation strategies for reducing tree-kangaroo road mortality. Implications Our findings suggest that tree-kangaroo road-kill can be reduced by reducing speed limits in line with government recommendations and increasing visibility by clearing road verges along sections of road with the highest tree-kangaroo mortality. Warning signage should be re-evaluated to determine whether its effectiveness can be improved.
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Thompson, James, Matthew Baldock, and Tori Lindsay. "Motorcycle crashes resulting in hospital admissions in South Australia: Crash characteristics and injury patterns." Journal of Road Safety 31, no. 1 (February 1, 2020): 10–19. http://dx.doi.org/10.33492/jrs-d-19-00245.
Повний текст джерелаАнотація:
Motorcycle riders have a high risk of serious injury if they crash. To assist with identification of countermeasures, the present study examined records from the Royal Adelaide Hospital (RAH) in South Australia for 763 motorcyclists (including scooter riders) admitted between January 2008 and November 2010 and between April 2014 and December 2016. Records were linked with police-reported crash data and results of forensic blood tests for alcohol and drugs. When compared with 1617 car drivers admitted to the RAH over the same periods, motorcyclists were younger, were more commonly male, more likely to hold a learner permit, less likely to hold a provisional licence, less likely to be over the legal alcohol limit and less likely to be at-fault in multiple vehicle crashes. Their crashes were more likely to be single vehicle crashes (specifically roll over, left road – out of control and hit object/animal/pedestrian on road crashes) and were more common on weekends, during the afternoon, on sloping roads, on curved roads, on roads with speed limits of 50 and 80 km/h, during daylight hours, in dry weather and on dry roads. They had a higher severity of injury than car drivers, spent longer in hospital, and were more likely to sustain injuries to multiple body regions. Linear regression showed that older age, higher blood alcohol concentration and higher speed limit increased injury severity for motorcyclists. Based on present findings, motorcycling safety can be improved through countermeasures related to Graduated Licensing Systems, infrastructure, motorcycle technology and protective clothing.
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Buchheit, Martin, Hani Al Haddad, Ben M. Simpson, Dino Palazzi, Pitre C. Bourdon, Valter Di Salvo, and Alberto Mendez-Villanueva. "Monitoring Accelerations With GPS in Football: Time to Slow Down?" International Journal of Sports Physiology and Performance 9, no. 3 (May 2014): 442–45. http://dx.doi.org/10.1123/ijspp.2013-0187.
Повний текст джерелаАнотація:
The aims of the current study were to examine the magnitude of between-GPS-models differences in commonly reported running-based measures in football, examine between-units variability, and assess the effect of software updates on these measures. Fifty identical-brand GPS units (15 SPI-proX and 35 SPIproX2, 15 Hz, GPSports, Canberra, Australia) were attached to a custom-made plastic sled towed by a player performing simulated match running activities. GPS data collected during training sessions over 4 wk from 4 professional football players (N = 53 files) were also analyzed before and after 2 manufacturersupplied software updates. There were substantial differences between the different models (eg, standardized difference for the number of acceleration >4 m/s2 = 2.1; 90% confidence limits [1.4, 2.7], with 100% chance of a true difference). Between-units variations ranged from 1% (maximal speed) to 56% (number of deceleration >4 m/s2). Some GPS units measured 2–6 times more acceleration/deceleration occurrences than others. Software updates did not substantially affect the distance covered at different speeds or peak speed reached, but 1 of the updates led to large and small decreases in the occurrence of accelerations (–1.24; –1.32, –1.15) and decelerations (–0.45; –0.48, –0.41), respectively. Practitioners are advised to apply care when comparing data collected with different models or units or when updating their software. The metrics of accelerations and decelerations show the most variability in GPS monitoring and must be interpreted cautiously.
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Wietfeldt, R., W. Van Straten, D. Del Rizzo, N. Bartel, W. Cannon, M. Bailes, J. Reynolds, and W. Wilson. "The S2 Baseband Processing System for Phase-coherent Pulsar Observations." International Astronomical Union Colloquium 160 (1996): 21–22. http://dx.doi.org/10.1017/s0252921100040926.
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AbstractThe phase-coherent recording of pulsar data and subsequent software dispersion removal provide a flexible way to reach the limits of high time resolution, useful for more precise pulse timing and the study of fast signal fluctuations within a pulse. Because of the huge data rate and lack of adequate recording and computing capabilities, this technique has been used mostly only for small pulsar data sets. In recent years, however, the development of very capable, reasonably inexpensive high-speed recording systems and computers has made feasible the notion of pulsar baseband recording and subsequent processing with a workstation/computer. In this paper we discuss the development of a phase-coherent baseband processing system for radio pulsar observations. This system is based on the S2 VLBI recorder developed at ISTS/York University in Toronto, Canada. We present preliminary first results for data from the Vela pulsar, obtained at Parkes, Australia, and processed at ISTS/York University, and discuss plans for future developments.
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Anderson, Wendy R., Miguel G. Cruz, Paulo M. Fernandes, Lachlan McCaw, Jose Antonio Vega, Ross A. Bradstock, Liam Fogarty, et al. "A generic, empirical-based model for predicting rate of fire spread in shrublands." International Journal of Wildland Fire 24, no. 4 (2015): 443. http://dx.doi.org/10.1071/wf14130.
Повний текст джерелаАнотація:
A shrubland fire behaviour dataset was assembled using data from experimental studies in Australia, New Zealand, Europe and South Africa. The dataset covers a wide range of heathlands and shrubland species associations and vegetation structures. Three models for rate of spread are developed using 2-m wind speed, a wind reduction factor, elevated dead fuel moisture content and either vegetation height (with or without live fuel moisture content) or bulk density. The models are tested against independent data from prescribed fires and wildfires and found to predict fire spread rate within acceptable limits (mean absolute errors varying between 3.5 and 9.1 m min–1). A simple model to predict dead fuel moisture content is evaluated, and an ignition line length correction is proposed. Although the model can be expected to provide robust predictions of rate of spread in a broad range of shrublands, the effects of slope steepness and variation in fuel quantity and composition are yet to be quantified. The model does not predict threshold conditions for continuous fire spread, and future work should focus on identifying fuel and weather factors that control transitions in fire behaviour.
Дисертації з теми "Speed limits Australia"
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Abdul, Hanan Suhaila. "An application of an extended theory of planned behaviour to understand drivers' compliance with the school zones speed limit in Australia and Malaysia." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/72899/2/Suhaila_Abdul_Hanan_Thesis.pdf.
Повний текст джерелаАнотація:
This research investigated individual and situational factors that influence driver compliance with the school zones speed limit in Australia and Malaysia. Despite all the countermeasures implemented in these two countries, driver compliance with the speed limit in school zones is still poor.
The findings of the research provided support for the application of the Theory of Planned Behaviour to understand and therefore influence drivers' intention to comply with the school zones speed limit in both Australia and Malaysia. The research also revealed that mindfulness, a construct rarely used in road safety before, directly influenced Australian drivers' intention to comply, while habit influenced intention to comply in Malaysia. The research raised important theoretical and cross-cultural issues for future research and highlighted the need to increase the visibility of school zones with the use of more noticeable traffic control devices.
Частини книг з теми "Speed limits Australia"
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Fildes, Brian N., Brendan Lawrence, Luke Thompson, and Jennie Oxley. "Speed-Limits in Local Streets: Lessons from a 30 km/h Trial in Victoria, Australia." In The Vision Zero Handbook, 881–901. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-76505-7_34.
Повний текст джерелаАнотація:
AbstractFatal and Severe Injuries (FSI) to vulnerable road users is a major road safety problem internationally. Recent resolutions by the Global Ministerial Conference on Road Safety called for a blanket 30 km/h speed limit in urban areas to address this problem. A project undertaken in Melbourne, Australia, set out to evaluate the effectiveness and benefits of a lower speed limit in a local residential area in the City of Yarra. The intervention comprised replacing 40 km/h speed limit signs in the treated area with 30 km/h signs with an adjacent untreated control area. A before and after study was employed with speed, resident surveys, and estimated safety benefits as measures of its success. Modest reductions in mean speed were observed in the after-phase of the study while benefits were impressive for vehicles travelling at higher speed levels where the risk of severe injury or death is greater. These findings represent an estimated 4% reduction in the risk of severe injury for pedestrians in the event of a collision. Questionnaire responses showed an increased degree of support for the 30 km/h speed limit in local streets in the trial area. The implication of these findings for road safety is discussed, along with the challenges and potential hurdles. Lower speed limits in local streets and municipalities is one important measure to help address vulnerable road users in residential local streets.
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Fildes, Brian N., Brendan Lawrence, Luke Thompson, and Jennie Oxley. "Speed-Limits in Local Streets: Lessons from a 30 km/h Trial in Victoria, Australia." In The Vision Zero Handbook, 1–22. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-23176-7_34-1.
Повний текст джерелаАнотація:
AbstractFatal and Severe Injuries (FSI) to vulnerable road users is a major road safety problem internationally. Recent resolutions by the Global Ministerial Conference on Road Safety called for a blanket 30 km/h speed limit in urban areas to address this problem. A project undertaken in Melbourne, Australia, set out to evaluate the effectiveness and benefits of a lower speed limit in a local residential area in the City of Yarra. The intervention comprised replacing 40 km/h speed limit signs in the treated area with 30 km/h signs with an adjacent untreated control area. A before and after study was employed with speed, resident surveys, and estimated safety benefits as measures of its success. Modest reductions in mean speed were observed in the after-phase of the study while benefits were impressive for vehicles travelling at higher speed levels where the risk of severe injury or death is greater. These findings represent an estimated 4% reduction in the risk of severe injury for pedestrians in the event of a collision. Questionnaire responses showed an increased degree of support for the 30 km/h speed limit in local streets in the trial area. The implication of these findings for road safety is discussed, along with the challenges and potential hurdles. Lower speed limits in local streets and municipalities is one important measure to help address vulnerable road users in residential local streets.
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Cockfield, Samantha, David Healy, Anne Harris, Allison McIntyre, and Antonietta Cavallo. "The Development of the “Vision Zero” Approach in Victoria, Australia." In The Vision Zero Handbook, 1–33. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-23176-7_17-1.
Повний текст джерелаАнотація:
AbstractFor many decades, road safety measures in Australia focused almost exclusively on behavioral approaches. When Claes Tingvall was appointed Director of MUARC, he introduced the concept of “Vision Zero” to Australia and, with it, the “Safe System” approach. While political leaders initially regarded a vision for zero deaths as unachievable, they supported the inherent logic of the Safe System.Initially the Safe System was applied as four independent pillars. While this lack of integration had limitations, it did enable road safety measures to move beyond road user behavior to focus more on safer road infrastructure and vehicle safety.The initial Safe System approach became “Towards Zero” an approach that accepts humans are fragile, and the road system designed to protect from death or serious injury was adopted across all Australia jurisdictions between 2004 and 2018.Public education has been used to introduce and explain Towards Zero and bring greater attention to the importance of purchasing a safe vehicle. Infrastructure investment has moved from a “blackspot” approach to the Safe System approach. However, shifting community and decision-makers’ understanding of the importance of speed limits being set to match the safety standard and design of a road remains a challenge. Future opportunities involve better integration of the components of the Safe System, focusing on serious injuries and improving strategy delivery, performance reporting, management, and accountability.
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Cockfield, Samantha, David Healy, Anne Harris, Allison McIntyre, and Antonietta Cavallo. "The Development of the “Vision Zero” Approach in Victoria, Australia." In The Vision Zero Handbook, 475–506. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-76505-7_17.
Повний текст джерелаАнотація:
AbstractFor many decades, road safety measures in Australia focused almost exclusively on behavioral approaches. When Claes Tingvall was appointed Director of MUARC, he introduced the concept of “Vision Zero” to Australia and, with it, the “Safe System” approach. While political leaders initially regarded a vision for zero deaths as unachievable, they supported the inherent logic of the Safe System.Initially the Safe System was applied as four independent pillars. While this lack of integration had limitations, it did enable road safety measures to move beyond road user behavior to focus more on safer road infrastructure and vehicle safety.The initial Safe System approach became “Towards Zero” an approach that accepts humans are fragile, and the road system designed to protect from death or serious injury was adopted across all Australia jurisdictions between 2004 and 2018.Public education has been used to introduce and explain Towards Zero and bring greater attention to the importance of purchasing a safe vehicle. Infrastructure investment has moved from a “blackspot” approach to the Safe System approach. However, shifting community and decision-makers’ understanding of the importance of speed limits being set to match the safety standard and design of a road remains a challenge. Future opportunities involve better integration of the components of the Safe System, focusing on serious injuries and improving strategy delivery, performance reporting, management, and accountability.
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Barrows, Clayton, and Michael Robinson. "Introduction to Clubs." In Club Management. Goodfellow Publishers, 2018. http://dx.doi.org/10.23912/9781911635062-3977.
Повний текст джерелаАнотація:
Private clubs have existed for as long as people have desired to gather in groups to do things together. It has been suggested that private clubs (and their predecessors) date to the Roman baths but probably pre-date even those. It is doubtful that the Roman baths represented the first time people congregated in groups to socialize, discuss commerce, politics, or just engage in a mutually agreeable activity. Certainly, most agree that the ‘modern’ clubs (in the English speaking world) originated in England, were limited to ‘gentlemen’ and organized for social, political, business and/or pleasure reasons. The concept was then ‘exported’ along with ex-patriots all around the world. Clubs have since evolved to the point where they exist in countries around the world although they are embraced to a greater or lesser extent in different places. Examples of private clubs can be found in such countries as England (and the greater UK), Ireland, the United States, Canada, Australia and New Zealand, South Africa, Switzerland, Hong Kong, India, Pakistan, Japan, Singapore, and the UAE. Perhaps no country has adopted the idea of clubs as much as the USA, where they have evolved into a veritable industry, are protected by law, and number into the thousands. Humans, being social creatures, long to spend quality time with others – ‘others’, historically, representing those of their own kind. Perhaps it is for this reason that clubs have, rightly or wrongly, developed a reputation for being discriminatory. People generally find benefits from spending time with others. These benefits may accrue in many forms, including personal, professional, and political.
Тези доповідей конференцій з теми "Speed limits Australia"
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Bashir, Sajid, Sammana Batool, Muhammad Imran, and Usman Ali. "Development of Frequency Limited Model Reduction Algorithm with Error Bound and Application to Continuous-Time Variable-Speed Wind Turbines for Power System." In 2020 Australian and New Zealand Control Conference (ANZCC). IEEE, 2020. http://dx.doi.org/10.1109/anzcc50923.2020.9318388.
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Babanin, Alexander V. "Wave-Induced Turbulence, Linking Metocean and Large Scales." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18373.
Повний текст джерелаАнотація:
Abstract Until recently, large-scale models did not explicitly take account of ocean surface waves which are a process of much smaller scales. However, it is rapidly becoming clear that many large-scale geophysical processes are essentially coupled with the surface waves, and those include ocean circulation, weather, Tropical Cyclones and polar sea ice in both Hemispheres, climate and other phenomena in the atmosphere, at air/sea, sea/ice and sea/land interface, and many issues of the upper-ocean mixing below the surface. Besides, the wind-wave climate itself experiences large-scale trends and fluctuations, and can serve as an indicator for changes in the weather climate. In the presentation, we will discuss wave influences at scales from turbulence to climate, on the atmospheric and oceanic sides. At the atmospheric side of the interface, the air-sea coupling is usually described by means of the drag coefficient Cd, which is parameterised in terms of the wind speed, but the scatter of experimental data with respect to such dependences is very significant and has not improved noticeably over some 40 years. It is argued that the scatter is due to multiple mechanisms which contribute into the sea drag, many of them are due to surface waves and cannot be accounted for unless the waves are explicitly known. The Cd concept invokes the assumption of constant-flux layer, which is also employed for vertical profiling of the wind measured at some elevation near the ocean surface. The surface waves, however, modify the balance of turbulent stresses very near the surface, and therefore such extrapolations can introduce significant biases. This is particularly essential for buoy measurements in extreme conditions, when the anemometer mast is within the Wave Boundary Layer (WBL) or even below the wave crests. In this presentation, field data and a WBL model are used to investigate such biases. It is shown that near the surface the turbulent fluxes are less than those obtained by extrapolation using the logarithmic-layer assumption, and the mean wind speeds very near the surface, based on Lake George field observations, are up to 5% larger. The dynamics is then simulated by means of a WBL model coupled with nonlinear waves, which revealed further details of complex behaviours at wind-wave boundary layer. Furthermore, we analyse the structure of WBL for strong winds (U10 > 20 m/s) based on field observations. We used vertical distribution of wind speed and momentum flux measured in Topical Cyclone Olwyn (April 2015) in the North-West shelf of Australia. A well-established layer of constant stress is observed. The values obtained for u⁎ from the logarithmic profile law against u⁎ from turbulence measurements (eddy correlation method) differ significantly as wind speed increases. Among wave-induced influences at the ocean side, the ocean mixing is most important. Until recently, turbulence produced by the orbital motion of surface waves was not accounted for, and this fact limits performance of the models for the upper-ocean circulation and ultimately large-scale air-sea interactions. While the role of breaking waves in producing turbulence is well appreciated, such turbulence is only injected under the interface at the vertical scale of wave height. The wave-orbital turbulence is depth-distributed at the scale of wavelength (∼10 times the wave height) and thus can mix through the ocean thermocline in the spring-summer seasons. Such mixing then produces feedback to the large-scale processes, from weather to climate. In order to account for the wave-turbulence effects, large-scale air-sea interaction models need to be coupled with wave models. Theory and practical applications for the wave-induced turbulence will be reviewed in the presentation. These include viscous and instability theories of wave turbulence, direct numerical simulations and laboratory experiments, field and remote sensing observations and validations, and finally implementations in ocean, Tropical Cyclone, ocean and ice models. As a specific example of a wave-coupled environment, the wave climate in the Arctic as observed by altimeters will be presented. This is an important topic for the Arctic Seas, which are opening from ice in summer time. Challenges, however, are many as their Metocean environment is more complicated and, in addition to winds and waves, requires knowledge and understanding of ice material properties and its trends. On one hand, no traditional statistical approach is possible since in the past for most of the Arctic Ocean there was limited wave activity. Extrapolations of the current trends into the future are not feasible, because ice cover and wind patterns in the Arctic are changing. On the other hand, information on the mean and extreme wave properties is of great importance for oceanographic, meteorological, climate, naval and maritime applications in the Arctic Seas.
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Qi, Jianhui, Thomas Reddell, Kan Qin, Kamel Hooman, and Ingo H. J. Jahn. "Supercritical CO2 Radial Turbine Design Performance as a Function of Turbine Size Parameters." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-58137.
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Supercritical CO2 (sCO2) radial inflow turbine are an enabling technology for small scale concentrated solar thermal power. They are a research direction of the Australian Solar Thermal Research Initiative (ASTRI). This study uses the 1D meanline design code TOPGEN, to explore the radial turbine design space under consideration of sCO2 real gas properties. TOPGEN maps a parametric design space defined by flow and head coefficient. The preliminary design code is used explore the feasibility, geometry and performance of sCO2 turbines in the 100kW to 200kW range in order to assess feasible design spaces and to investigate turbine scaling. Turbines are scaled with respect to power, while maintaining specific speed constant and with respect to speed. This analysis shows that both scaling approaches change the feasible design space and that both geometric constraints such as blade height or operational constraints such as blade natural frequency can significantly limit the design space. Detailed analysis of four shortlisted designs shows that turbine efficiencies close to 85% can be attained for 100kW and 200kW output powers, even when operating at reduced rotor speeds. This work provides new insight towards the design of small scale radial turbines for operation with sCO2 and highlights scaling issues that may arise when testing sub-scale turbine prototypes.
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Whelan, J. R., Y. Drobyshevski, and J. D. McConochie. "Frequency and Time Domain Analyses of Vessel Motions During Tropical Cyclones." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-80098.
Повний текст джерелаАнотація:
A permanently turret moored floating facility located off the North West coast of Australia is likely to be exposed to tropical cyclones, which exhibit extreme wave height, wind and surface currents. Furthermore the cyclonic eye and fringes are characterised by rapidly varying metocean conditions, particularly wind speed and direction. It is necessary to understand the weather vaning and motion responses of the vessel during these transient conditions for successful facility development. This paper presents weather vaning and motion analyses of a Floating Storage and Offloading (FSO) vessel during the passage of tropical cyclones. A synthetic tropical data base developed by Woodside Energy Limited was used to generate the cyclonic conditions. The data base contains storms with return periods ranging from 10 to 100,000 years. Time histories of wave spectrum, wind and current at half-hourly intervals for several cyclones were examined. The weather vaning and motions responses of the FSO were computed using two methods: (1) a frequency domain quasi-stationary approach, and (2) a time domain approach. In the frequency domain analyses the metocean conditions were treated as stationary for each half-hour interval and the mean vessel heading and most probable amplitudes of motions were calculated. In the time domain analyses, the time histories of metocean conditions were closely matched to the synthesised cyclonic conditions, and time histories of vessel heading and motion responses were generated. Multiple realisations were simulated for each cyclone to assess variability of results associated with wave train random seed. A key finding of the study is that the worst roll response tends to occur after the eye of the cyclone has passed, at which time the wind and waves were highly non-collinear. At this time the vessel weather vanes so as to experience waves which are substantially beam-on. When the cyclonic eye is directly over the site, there is a reduction in wind speed and as a consequence the vessel weather vanes into the sea. This causes a corresponding reduction in the roll response. Results from both analysis methods have been compared and good agreement is observed. The applicability and limitations of the two analyses methods are also considered.
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Asadi, Sadegh, and Abbas Khaksar. "Analytical and Numerical Sand Production Prediction Calibrated with Field Data, Example from High-Rate Gas Wells." In SPE Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210776-ms.
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Abstract Sand production prediction is essential from the early stages of field development planning for well completion design and later for production management. Unconsolidated and weakly consolidated sandstones are prone to fail at low flowing bottom hole pressures during hydrocarbon production. To predict the sand-free drawdown, a robust sand prediction model that integrates near-wellbore and in-situ stresses, rock mechanical properties, well trajectory, reservoir pressure, production and depletion trends is required. Sanding prediction models should be calibrated with field data such as production and well tests observation. In the absence of field data, numerical techniques can provide a reliable estimate on potential onset and severity of sanding at various reservoir pressures. In this study, analytical and finite-element numerical models are independently used to predict the onset of sanding and volume of produced sand from high rate has wells with weakly consolidated sandstone reservoirs in onshore, Western Australia. The analytical method uses a poro-elastic model and core-calibrated log-derived rock strength profiles with an empirical effective rock strength factor (ESF). In the study, the ESF was calibrated against documented field sanding observation from a well test extended flow period at the initial reservoir pressure under a low drawdown pressure. The numerical method uses a poro-elasto-plastic model defined from triaxial core tests. The rock failure criterion in the numerical method is based on a critical strain limit (CSL) corresponding to the failure of the inner wall of thick-walled cylinder core tests that can also satisfy the existing wells sanding observations. To verify the onset and severity of sanding predicted by the analytical model, numerical simulations for an identical sandstone interval are developed to investigate the corresponding CSL. This combined analytical and numerical modelling calibrated with field data provided high confidence in the sanding evaluation and their application for future well completion and sand management decisions. The analytical model was finally used for sanding assessment over field life pressure condition because of its processing simplicity, speed and flexibility in assessing various pressure and rock strength scenarios with sensitivity analysis over the whole production interval in compared with the numerical method which is more suitable for single-depth, single pressure condition and well and perforation trajectory modelling.