Icing characteristics of a natural-laminar-flow, a medium-speed, and a swept, medium-speed airfoil

Tests were conducted at the Icing Research Tunnel at the NASA Lewis Research Center to determine the icing characteristics of three modern airfoils, a natural laminar flow, a medium speed and a swept medium speed airfoil. Tests measured the impingement characteristics and drag degradation for angles of attack typifying cruise and climb for cloud conditions typifying the range that might be encountered in flight. The maximum degradation occurred for the cruise angle of attack for the long glaze ice condition for all three airfoils with increases over baseline drag being 486 percent, 510 percent, and 465 percent for the natural laminar flow, the medium speed and the swept medium speed airfoil respectively. For the climb angle of attack, the maximum drag degradation (and extent of impingement) observed were also for the long glaze ice condition, and were 261 percent, 181 percent and 331 percent respectively. The minimum drag degradation (and extent of impingement) occurred for the cruise condition and for the short, rime spray which increases over baseline drag values of 47 percent, 28 percent and 46 percent respectively

Ice Accretion Prediction for a Typical Commercial Transport Aircraft

Ice accretion calculations were made for a modern commercial transport using the NASA Lewis LEWICE3D ice accretion code. The ice accretion calculations were made for the wing and horizontal tail using both isolated flow models and flow models incorporating the entire airplane. The isolated flow model calculations were made to assess the validity of using these simplified models in lieu of the entire model in the ice accretion analysis of full aircraft. Ice shapes typifying a rime and a mixed ice shape were generated for a 30 minute hold condition. In general, the calculated ice shapes looked reasonable and appeared representative of a rime and a mixed ice conditions. The isolated flow model simplification was good for the main wing except at the root where it overpredicted the amount of accreted ice relative to the full aircraft flow model. For the horizontal tail the size and amount of predicted ice compared well for the two flow models, but the position of the accretions were more towards the upper surface for the aircraft flow model relative to the isolated flow model. This was attributed to downwash from the main wing which resulted in a lower effective angle of attack for the aircraft tail

Numerical simulation of ice growth on a MS-317 swept wing geometry

An effort to develop a 3-D ice accretion modeling method was initiated. This first step towards creation of a complete aircraft icing simulation code builds on previously developed methods for calculating 3-D flow fields and particle trajectories combined with a 2-D ice accretion calculation along coordinate locations corresponding to streamlines. The types of calculations necessary to predict 3-D ice accretion is demonstrated. Results of calculations using 3-D method for a MS-317 swept wing geometry are projected onto a 2-D plane parallel to the free stream direction and compared to experimental results for the same geometry. It is anticipated that many modifications will be made to this approach, however this effort will lay the groundwork for future modeling efforts. Results indicate that rime ice shapes indicate a difficulty in accurately calculating the ice shape in the runback region

Swept wing ice accretion modeling

An effort to develop a three-dimensional modeling method was initiated. This first step towards creation of a complete aircraft icing simulation code builds on previously developed methods for calculating three-dimensional flow fields and particle trajectories combined with a two-dimensional ice accretion calculation along coordinate locations corresponding to streamlines. This work is a demonstration of the types of calculations necessary to predict a three-dimensional ice accretion. Results of calculations using the 3-D method for a MS-317 swept wing geometry are projected onto a 2-D plane normal to the wing leading edge and compared to 2-D results for the same geometry. It is anticipated that many modifications will be made to this approach, however, this effort will lay the groundwork for future modeling efforts. Results indicate that the flow field over the surface and the particle trajectories differed for the two calculations. This led to lower collection efficiencies, convective heat transfer coefficients, freezing fractions, and ultimately ice accumulation for the 3-D calculation

Comparison of two-dimensional and three-dimensional droplet trajectory calculations in the vicinity of finite wings

Computational predictions of ice accretion on flying aircraft most commonly rely on modeling in two dimensions (2D). These 2D methods treat an aircraft geometry either as wing-like with infinite span, or as an axisymmetric body. Recently, fully three dimensional (3D) methods have been introduced that model an aircrafts true 3D shape. Because 3D methods are more computationally expensive than 2D methods, 2D methods continue to be widely used. However, a 3D method allows us to investigate whether it is valid to continue applying 2D methods to a finite wing. The extent of disagreement between LEWICE, a 2D method, and LEWICE3D, a 3D method, in calculating local collection efficiencies at the leading edge of finite wings is investigated in this paper

The Effects of Information on Public Attitudes Toward Renewable Energy

The information-deficit model is a common framework for explaining public attitudes toward new technologies, including renewable energy technology. This model assumes that public opposition to technology is based on a lack of quality information. The siting of facilities, such as commercial wind farms, frequently face opposition from residents of local communities, despite broad public support for renewable energy. Although social science has been critical of the information-deficit model, providing information to the public can influence both the substance and quality of attitudes. In this study, residents of coastal communities in Michigan, supportive of wind energy on average, were provided in-depth information about wind energy. Compared with a control group, participants who attended information sessions exhibited greater change in both their general support for wind energy and the strength of those attitudes. Possible implications for the siting of wind farms and other renewable projects are discussed

Developmental coordination disorder (dyspraxia): what helps, what hinders in the school years for later achievement and wellbeing?

Background. Developmental Coordination Disorder (DCD) is a condition impacting physical coordination and organisation of movement. Poor central executive skills (planning, organising and prioritising) are also evident. The rate of anxiety and depression amongst pupils, young adults and adults experiencing DCD is greater than would be expected. / Aims. 1. To evaluate the evidence for social, emotional and educational difficulties associated with DCD during the school years. 2. To relate pupil experiences during key stages 4 and 5 with their wellbeing as young adults and with academic attainments. Literature review. Twenty three research papers were identified which addressed (i) the evidence which associates the physical manifestations of DCD with additional social, emotional, educational and cognitive difficulties, (ii) the theoretical perspectives put forward to account for these associated difficulties and (iii) interventions reported with consideration of their impact and useability. / Sample. The study participants were 26 young adults (aged 20 to 36) previously identified through the author’s private practice as experiencing possible dyspraxia together with their parents. / Methods. The study addressed two key questions and employed a mixed method exploratory design combining cross-sectional and predictive information (due to the availability of historical data) The participants completed online questionnaires. The young adult questionnaire covered school experiences, educational attainment, their current situation and reflections on their school experience. The parent questionnaire covered similar topics. / Results. A strong link was found between the young adults’ current wellbeing and their perceptions of the level of recognition and understanding of DCD shown by their teachers in school. Academic achievement was positively correlated with verbal ability; qualitative data indicates the benefit of parental support. / Conclusions. The identification of DCD amongst the school aged population is essential if later negative consequences are to be avoided. Teachers need input which will enable them to 1) recognise behaviours indicative of DCD and 2) provide a supportive learning and social environment. The evidence suggests that this would enable such pupils to thrive emotionally, achieve academically and minimise later mental health issues