title: Aerodynamics of two-dimensional sail wings

authors: Bundock, Michael Stephen

subjects: Aerodynamics

abstract: The purpose of this work is to obtain the exact solution for the profile and characteristics of a two-dimensional sail, immersed in an inviscid incompressible fluid. An experimental investigation was also performed and results are compared with theoretical predictions. 

The sail was assumed to be an infinitely flexible, non-porous membrane of zero thickness, fixed at the leading and trailing edges, and stretched under a constant tension T in the sail surface. An aerofoil model was considered where the airflow remains smoothly attached over the entire profile. 

All known previous studies have also used the inviscid fluid approximation, but made the further assumptions of small angle of attack and negligible profile slopes. These assumptions enable the use of thin aerofoil theory predictions for pressure distribution and linearisation of the sail equation.

In contrast this investigation obtains the exact solution. An iterative numerical method is devised whereby an initial estimate is made for the profile using thin aerofoil theory. The pressure distribution is then determined using Theodorsen's method and the profile recalculated using the full sail equation, so that tension and pressure forces are balanced. The cycle of redetermining the pressure distribution and profile is repeated until a convergent solution is obtained.

Results are shown for the profile, lift coefficient and centre of pressure, for various angles of attack and states of tension. For sails with non-negligible camber, values of lift coefficient and centre of pressure are found to differ significantly from those predicted by the linear approximations. Previous researchers have established the existence of a critical tension state where the tension force is unable to contain the pressure forces acting on the sail, and predicted that the value of this state (KTc) was independent of angle of attack. However this study indicates that KTc increases with increasing angle of attack. Centre of pressure calculations, for various angles of attack and states of tension, indicate that two-dimensional sails may possess either static longitudinal stability or instability, depending on the tension state. Experimental results for the profile, KTc, lift coefficient and centre of pressure are compared with theory, and areas of agreement and disagreement discussed. Experimental values for the drag coefficient and the lift to drag ratio were obtained and are discussed in detail.

text: Aerodynamics of two-dimensional sail wings The purpose of this work is to obtain the exact solution for the profile and characteristics of a two-dimensional sail, immersed in an inviscid incompressible fluid. An experimental investigation was also performed and results are compared with theoretical predictions. 

The sail was assumed to be an infinitely flexible, non-porous membrane of zero thickness, fixed at the leading and trailing edges, and stretched under a constant tension T in the sail surface. An aerofoil model was considered where the airflow remains smoothly attached over the entire profile. 

All known previous studies have also used the inviscid fluid approximation, but made the further assumptions of small angle of attack and negligible profile slopes. These assumptions enable the use of thin aerofoil theory predictions for pressure distribution and linearisation of the sail equation.

In contrast this investigation obtains the exact solution. An iterative numerical method is devised whereby an initial estimate is made for the profile using thin aerofoil theory. The pressure distribution is then determined using Theodorsen's method and the profile recalculated using the full sail equation, so that tension and pressure forces are balanced. The cycle of redetermining the pressure distribution and profile is repeated until a convergent solution is obtained.

Results are shown for the profile, lift coefficient and centre of pressure, for various angles of attack and states of tension. For sails with non-negligible camber, values of lift coefficient and centre of pressure are found to differ significantly from those predicted by the linear approximations. Previous researchers have established the existence of a critical tension state where the tension force is unable to contain the pressure forces acting on the sail, and predicted that the value of this state (KTc) was independent of angle of attack. However this study indicates that KTc increases with increasing angle of attack. Centre of pressure calculations, for various angles of attack and states of tension, indicate that two-dimensional sails may possess either static longitudinal stability or instability, depending on the tension state. Experimental results for the profile, KTc, lift coefficient and centre of pressure are compared with theory, and areas of agreement and disagreement discussed. Experimental values for the drag coefficient and the lift to drag ratio were obtained and are discussed in detail.

year: 1980

title: Collaboration across New Zealand rural primary schools: A virtual learning perspective

authors: Whalley, Rachel

subjects: rural education

abstract: The purpose of this thesis is to examine challenges faced by students and teachers at small rural schools, and explore how these may be alleviated by collaborative practice between schools in virtual learning environments. The design of this research is situated within an interpretivist framework and influenced by critical theory, as my research question seeks solutions to challenges that small rural schools face. Research participants were teaching principals selected from eight small rural New Zealand primary schools who were all active in Virtual Learning Network (VLN) Primary School online programmes, and so had current experience of collaborating, and teaching and learning online. Participants took part in focus group interviews, with two being interviewed individually a second time.  A grounded theory method of inductive analysis was used throughout the research process to generate findings from the data.

I found that there are many challenges in being a principal in a small rural school in New Zealand, but when principals work collaboratively across schools they can relieve some of those challenges and provide benefits for their students and themselves. Challenges for principals of small rural primary schools were identified as staffing difficulties, high workload, lack of time and access to professional learning and development, resources and support. These challenges were often compounded due to these schools being relatively small and geographically isolated. The participant’s’ experience of collaborating online highlighted a wide range of benefits for both themselves and their students, in providing access to a wider curriculum, developing digital fluency, reducing professional isolation and relieving workload. 

Throughout this study the unique nature of rural education was highlighted, with rural schools being acknowledged as providing a vital role in strengthening rural communities.  Recommendations are made to schools on how they can move towards learning in a collaborative online environment; and to government on how they can develop policy and provide resourcing to support small rural primary schools. With fast reliable internet, the small rural school that is open, networked and collaborative can increase its capacity to provide learning opportunities for both students and teachers.

text: Collaboration across New Zealand rural primary schools: A virtual learning perspective The purpose of this thesis is to examine challenges faced by students and teachers at small rural schools, and explore how these may be alleviated by collaborative practice between schools in virtual learning environments. The design of this research is situated within an interpretivist framework and influenced by critical theory, as my research question seeks solutions to challenges that small rural schools face. Research participants were teaching principals selected from eight small rural New Zealand primary schools who were all active in Virtual Learning Network (VLN) Primary School online programmes, and so had current experience of collaborating, and teaching and learning online. Participants took part in focus group interviews, with two being interviewed individually a second time.  A grounded theory method of inductive analysis was used throughout the research process to generate findings from the data.

I found that there are many challenges in being a principal in a small rural school in New Zealand, but when principals work collaboratively across schools they can relieve some of those challenges and provide benefits for their students and themselves. Challenges for principals of small rural primary schools were identified as staffing difficulties, high workload, lack of time and access to professional learning and development, resources and support. These challenges were often compounded due to these schools being relatively small and geographically isolated. The participant’s’ experience of collaborating online highlighted a wide range of benefits for both themselves and their students, in providing access to a wider curriculum, developing digital fluency, reducing professional isolation and relieving workload. 

Throughout this study the unique nature of rural education was highlighted, with rural schools being acknowledged as providing a vital role in strengthening rural communities.  Recommendations are made to schools on how they can move towards learning in a collaborative online environment; and to government on how they can develop policy and provide resourcing to support small rural primary schools. With fast reliable internet, the small rural school that is open, networked and collaborative can increase its capacity to provide learning opportunities for both students and teachers.

year: 2018

title: A short history of Te Mātāhauariki Research Institute

authors: Frame, Alex

abstract: Te Mātāhauariki Institute was established to continue the work of a research programme which had been established under a contract awarded under the Public Good Science Fund (PGSF), to the School of Law at the University of Waikato. This was the first law project to be so funded in New Zealand. The programme, titled "Laws and Institutions for a Bicultural New Zealand", was developed by Professors Paul Havemann and Margaret Bedggood, at the suggestion and under the guidance and encouragement of Professor Michael Selby, then Deputy Vice Chancellor in charge of Research. The design and writing of the programme itself was almost entirely the work of Professor Havemann. The funding granted initially was $450,000 for two years.

text: A short history of Te Mātāhauariki Research Institute Te Mātāhauariki Institute was established to continue the work of a research programme which had been established under a contract awarded under the Public Good Science Fund (PGSF), to the School of Law at the University of Waikato. This was the first law project to be so funded in New Zealand. The programme, titled "Laws and Institutions for a Bicultural New Zealand", was developed by Professors Paul Havemann and Margaret Bedggood, at the suggestion and under the guidance and encouragement of Professor Michael Selby, then Deputy Vice Chancellor in charge of Research. The design and writing of the programme itself was almost entirely the work of Professor Havemann. The funding granted initially was $450,000 for two years.

year: 2010-2011