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An investigation was carried out into external-Coanda Effect flares designed by British Petroleum International plc. The phenomenon of interest was breakaway of an under expanded axisymmetric curved wall jet from the guiding surface due to high blowing pressure. A survey of investigations of similar flows suggested very complex jet fluid dynamics. Strong cell structure including shock waves was present giving bulk and discrete compression and bulk dilatation. More expansion was imposed by the radial velocity components. Wall curvature and a rear-facing step added further significant influences. The combination of these factors is known to produce highly non-linear turbulence, and this constitutes a major difficulty for the application of computational methods to the flare. In view of the amount of resources required to eliminate the problems of using a Navier-Stokes code, an economical approach was adopted, matching the Method of Characteristics to various simplified models and an integral boundary layer. In the experimental work, a planar model of the flare was contructed and studied using a wide range of methods in order to achieve accuracy and provide comparability with other work. An axisymmetric model was designed and investigated in a similar manner, so that the influence of this geometry could be clearly distinguished. A full-scale flare was subjected to a restricted range of tests to compare the laboratory results with the industrial application. The results from all the experiments demonstrated good correspondence. The main conclusion was that amalgamation of separation bubbles is crucial for breakaway. These are present long before breakaway, and are strongly reduced by decreasing the cell scale, adding a rear-facing step and axisymmetry, which leads to improved breakaway performance. Although the computational methods did not prove robust enough for all design purposes, they did permit significant insights into the mechanism of breakaway.

<p> Given the pervasion of multi-touch tablet, pen-based applications have rapidly moved onto this new platform. Users draw both with bare fingers and using capacitive pens as they would do on paper in the past. Unlike paper, these tablets cannot distinguish legitimate finger/pen input from accidental touches by other parts of the user's hand. In this thesis, we refer it to as errant touch rejection problem since users may unintentionally touch the screen with other parts of their hand. </p><p> In this thesis, I design, implement and evaluate new approaches, bezel-focus rejection, of preventing errant touches on multi-touch tablets. I began the research by conducting a formal study to collect and characterize errant touches. I analyzed the data collected from the study and the results are guiding me to design rejection techniques. I will conclude this research by developing bezel-focus rejection and evaluate its performance. The results show that bezel-focus rejection yields high rejection rate of errant touches and make users more inclined to rest hands on tablet than comparison techniques. </p><p> This research has two major contributions to Human Computer Interaction (HCI) community. First, my proposed errant touch rejection approaches can be applied the other pen-based note-taking applications. Second, my experimental results can serve as a guide to other developing similar techniques.</p>