1,721,078 research outputs found
Mission based optimum system selector for bio-inspired unmanned untethered underwater vehicles
No full textThis paper is a part of the Nature in Engineering for Monitoring the Oceans (NEMO) project, investigating bio-inspiration to improve the performance of Unmanned Untethered Underwater Vehicles (UUUVs). Since biological systems (i.e. marine animals) are natives to the oceans, successfully surviving through time, they have been the source of this approach.</p
Design, build and testing of a laminar flow drag-plate
No full textTheory indicates that compliant materials are able to reduce the frictional drag of a marine body by delaying the transition from laminar to turbulent flow.Recent experimentation on relatively small samples of compliant material suggest that correctly designed compliant materials are able to damp instabilities in the boundary layer and delay transition.In this research the challenge was to design a device that could be used to test relatively large panels of complaint material and subsequently use the device to make an experimental comparison between the drag of complaint material and a standard non-compliant surface. In particular, the principal requirement of the test device was that laminar flow persisted over the leading edge and was incident on the compliant material surface over the desired test speed range. A drag-plate with a laminar flow nose section was designed for this purpose.In the first part of this thesis basic drag assessments are made using engineering formulae followed by a rigorous computational assessment of fluid flow, boundary layer properties and transition prediction for alternative laminar flow drag-plates.An optimum geometry is established for the laminar flow nose and other practical design requirements are assessed, resulting in the final design of the laminar flow drag-plate. In addition a suitable dynamometer with associated fixtures is designed.In the second part of this thesis, the experimental facility is characterised and experimental procedures established.The drag of a compliant material is compared to a standard non-compliant material. No drag reduction was evident, although the compliant material (supplied from an external source) had inconsistencies in manufacture.A number of different demonstrations of the laminar flow performance of the drag-plate are presented. These include a novel practical transition detection method and flow visualisation. It is demonstrated that the design challenge of producing a laminar flow device has been achieved despite the fact that the drag-plate exhibits a degree of roughening over the experimental period
Exhaust gas emissions from regional shipping: mitigating technologies and emission prediction
No full textThe effects of exhaust gas emissions from all modes of shipping are a subject of concern for two main reasons. Firstly, they contribute CO 2, causing anthropogenic global climate change and, secondly, other exhaust gas species, e.g. PM, NO x, SO x, are detrimental to environmental and human health. This second point is of particular concern where high-levels of shipping activity occur in regions of high population density. To address this, there are a variety of technological mitigation methods and devices. This paper provides an analysis of these technologies in terms of their effectiveness and suitability against a range of exhaust gas species of interest. Furthermore, another approach to reduce harmful emissions is to modify the way in which ships are operated, and this requires accurate prediction of emissions for all operational conditions, machinery and ship types. This paper therefore also reports on research being conducted to predict these emissions.</p
Staff exchange teaching model for an offshore campus
No full textIn 2009 an offshore campus was set up in Singapore by the School of Marine Science and Technology, Newcastle University. Three maritime engineering programs are delivered successfully with approximately 80 students graduating annually. With recent addition of other schools and new staff members to offshore campus, a staff exchange teaching model is initiated by a specialist team of staff with objectives to enhance student experience and possibility of research project tie-ups between the two campuses. Key performance indicators of success will be results of assessment and student feedback as well as evaluation by education specialist at the end of project.</p
A practical and robust method to experimentally determine the location of the region of transition from laminar to turbulent flow on a towed body
No full textWhen performing model-scale resistance tests on bodies towed in water it is normal practice to deliberately stimulate turbulence close to the leading edge to permit appropriate scaling of resistance measurements. Alternatively, tests on towed bodies can address the flow characteristics over the body in the absence of deliberately tripped turbulent flow. In the second case an appreciation of the extent of laminar and turbulent flow over the body is of particular interest. While sophisticated and expensive methods are available to experimentally detect the location of transition on bodies in fluid flow, these are still particularly challenging when applied on bodies being towed through water. In this paper a straightforward alternative experimental method to detect transition on towed bodies is provided. This transition detection method simply uses conventional experimental measurements of drag on a towed body, subject to deliberate turbulence stimulation, to deduce the extent of laminar flow. The transition detection method is theoretically outlined and an experimental flow visualisation procedure demonstrates the required effectiveness of the turbulence stimulators used. An experimental demonstration of the proposed method is provided using two alternative turbulence stimulation devices. The conclusions indicate that the proposed method provides a practical and robust method to experimentally detect transition on a towed body with reasonable accuracy
Evaluation of environmental performance indices for ships
No full textPollution from ships is a significant environmental concern. Maritime environmental legislation has tightened in recent years since the introduction of the MARPOL 73/78 regulations, however there is often a significant time gap between when the regulations are adopted and when they legally enter force. The emergence of private voluntary environmental initiatives has occurred in an attempt to bridge this gap, reduce environmental impacts, and raise the environmental profile of ships. However, there are inconsistencies in the methodologies used to define ship performance, and the number and diversity of initiatives available for use can cause confusion, hindering progress towards greater sustainability. A critical analysis of existing environmental initiatives in the shipping industry has been conducted, challenging the applicability, scope, and environmental ambition of the methodologies adopted. The analysis highlights significant limitations of initiatives with regards to transparency, assessment rationale and environmental scope, and flexibility to be ship specific. Many show bias towards certain environmental indicators, while others have limited ambition. This paper challenges the effectiveness of existing environmental initiatives used in the shipping sector to promote environmental improvements beyond current regulatory requirements, and proposes an objective, quantifiable approach to assessing vessel environmental performance.</p
Decarbonising the UK fleet: a life cycle assessment of alternative marine fuels. Review of marine alternative fuels and their development
No full textHolistic energy mapping methodology for reduced fuel consumption and emissions
No full textThere are increasing concerns and regulations regarding the emission of pollutants from shipping. Therefore, regulations such as the Ship Energy Efficiency Management Plan (SEEMP) and Energy Efficiency Design Index (EEDI) have been made mandatory to cope with climate change concerns. To put these efforts into practice, the Energy Efficiency Operational Indicator (EEOI) was introduced in 2009 to account for the fuel consumption, distance travelled by the vessel and cargo mass. However, it is stated that these do not apply to ships that are not engaged in transport work such as research vessels and tugboats. These short sea shipping vessels have been neglected under current indexes and it is not possible for their properties to be quantified since current indices are for vessels carrying loads. The numbers of these specialised vessels are increasing in local waters, and are closer to coastal communities where concerns and impact from these pollutants would be more direct. In the IMO greenhouse gas study, options for improving energy efficiency in terms of design includes the concept, design speed and capability, hull and superstructure, power and propulsion whilst the principle of energy efficiency in terms of operation includes fleet management, logistics and incentives, voyage optimisation and energy management. A reliable energy flow breakdown architecture and diagnostics for these smaller vessels is important and will contribute to an understanding of the energy production, distribution and consumption on-board. This feeds into the IMO plan to encourage energy management. A systematic approach consisting of five distinct stages is recommended to accomplish a holistic approach for energy efficiency management. This includes understanding of energy flow breakdown architecture, vessel survey to understand operation and conduct, review existing sensors and new sensor installation, sensor communication and data processing, and finally data analysis. These stages are addressed in this paper to provide an overall understanding of a robust energy efficiency audit procedure and sensor matrix. This includes unifying the existing on-board sensors with the proposed new sensors for additional data collection where primary parameters are not readily available. Inferred secondary parameter calculations are also applied where direct data collection is not possible. This will allow information from the vessel to be transmitted to a common platform to enable detailed data analysis. The aim of this work is to improve energy management and monitoring, which leads to understanding and managing consumption of energy. A case study of this methodology has been carried out on the Princess Royal, a Newcastle University research vessel. Recommendations for further testing and optimisation of this methodology will be applied to tugboats and Offshore Supply Vessels (OSV)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
