An aeroacoustic investigation into the effect of self-oscillating trailing edge flaplets

The aeroacoustics of a NACA 0012 aerofoil with an array of self-oscillating flexible flaplets attached on the trailing edge has been investigated at low to moderate chord based Reynolds number (50,000 -- 350,000) and at geometric angles of attack from $\alpha_g = 0^\circ$ -- $20^\circ$. When the aerofoil is untripped, tonal peaks are observed on the baseline aerofoil. When the passive flaplets are attached to the pressure side of the aerofoil, the tonal peak is removed. If the flaplets are then placed on the suction side, the tonal peak is reduced, but not removed. It is therefore hypothesised that the flaplets on the pressure side modifies the laminar separation bubble situated on the pressure side of the aerofoil, a key mechanism for tonal noise. Throughout all cases, both tripped and untripped, a low frequency (0.1 kHz -- 0.6 kHz) noise reduction and a slight increase at higher frequencies (>2 kHz) is seen. This gives an average overall sound pressure level (OSPL) reduction of 1.5 -- 2 dB for the flaplets affixed to the pressure side. The cases where the tonal noise component is removed an OSPL reduction of up to 20 dB can be seen

Upstream Shear Layer Stabilisation via Self-Oscillating Trailing Edge Flaplets

The flow around a symmetric aerofoil (NACA 0012) with an array of flexible flaplets attached to the trailing edge has been investigated at Reynolds numbers of 100,000 - 150,000 by using time resolved particle image velocimetry (TR-PIV) and high speed motion tracking of the flaplets' tips. Particular attention has been made on the upstream effect on the boundary layer evolution along the suction side of the wing. For the plain aerofoil, without flaplets, the boundary layer on the second half of the wing undergoes shear-layer roll-up in the fundamental mode, but with rapid growth of non-linear modes which initiate the merging of rollers. When the flaplets are attached, it is shown that the flow-induced oscillations of the flaplets are able to create a lock-on effect that stabilises the linear state of the shear layer whilst damping the growth of non-linear modes. In addition, it is concluded that the modified trailing edge reduces aeroacoustic noise production in the lower frequency band, as indicated by an initial acoustic investigation

Doctor of Philosophy

dissertationThe purpose of this study was to characterize sexual harassment in public, or ‘eve teasing', in rural India, develop a measurement tool, and to estimate its prevalence and association with common mental disorders (CMD) and suicide ideation (SI) among young women. Mixed methods included focus group discussions, direct observation of questionnaire administration, and both qualitative and quantitative data gathering with a novel questionnaire. Females ages 14-26 were recruited through purposive sampling in nine villages for the initial pretest (N=89). Using the finalized questionnaire, we conducted a cross-sectional survey using a randomized cluster sample of 19 villages and recruited 198 women ages 15-24 using house-to-house probability sampling. Eve teasing was described as staring, stalking, passing comments, or inappropriate physical touch. Most participants perceived significant negative consequences, including tight restrictions on girls' mobility, inability to attend school or work, girl's being blamed, and causing family problems. Among those who reported eve teasing victimization, psycho-social responses included feelings of fear (88%), anger (78%), and shame (68%) (N=59). The internal reliability of the questionnaire was high for key measures (Cronbach's alpha: .65 to .84) and principal components analysis suggested two underlying constructs in the eve teasing instrument. Nearly 30% of participants reported ever having been eve teased, 21% screened positive for a CMD, and 27% reported recent suicide ideation (N=198). In multivariate analyses, spending more than 1 hour in public daily was associated with iv reported eve teasing (OR: 3.1 (CI: 1.26-7.49) p=0.016). The odds of screening positive for CMD were significantly higher if eve teased, but only among participants who reported adverse childhood events (ACEs) (OR: 4.5 (CI: 1.18-11.43) p=0.003). Eve teasing was significantly associated with SI among participants who reported ACEs when CMD were included in the model (OR: 3.1 (CI: 1.119-8.472) p=0.032). This is the first study, to our knowledge, to assess the association between eve teasing victimization and mental health outcomes in a community setting. We found that eve teasing may negatively impact the mental health of young women, especially victims of child abuse, and offer a reliable and valid questionnaire for future research

An aeroacoustic investigation into the effect of self-oscillating trailing edge flaplets

The aeroacoustics of a NACA 0012 aerofoil with an array of self-oscillating flexible flaplets attached on the trailing edge has been investigated at low to moderate chord based Reynolds number (50,000 -- 350,000) and at geometric angles of attack from $\alpha_g = 0^\circ$ -- $20^\circ$. When the aerofoil is untripped, tonal peaks are observed on the baseline aerofoil. When the passive flaplets are attached to the pressure side of the aerofoil, the tonal peak is removed. If the flaplets are then placed on the suction side, the tonal peak is reduced, but not removed. It is therefore hypothesised that the flaplets on the pressure side modifies the laminar separation bubble situated on the pressure side of the aerofoil, a key mechanism for tonal noise. Throughout all cases, both tripped and untripped, a low frequency (0.1 kHz -- 0.6 kHz) noise reduction and a slight increase at higher frequencies (>2 kHz) is seen. This gives an average overall sound pressure level (OSPL) reduction of 1.5 -- 2 dB for the flaplets affixed to the pressure side. The cases where the tonal noise component is removed an OSPL reduction of up to 20 dB can be seen

A short history of India and the frontier states of Afghanistan, Nipal, and Burma (1884)

19th century history of India, Afghanistan, Nepal and Burma

Creative Solutions : how Students With Occupational Overuse Syndrome (OOS) Conditions Manage Their Studies at Victoria University of Wellington

The barriers that prevent people with disabilities from accessing and succeeding in post-compulsory education are well documented, as are the accommodations that tertiary institutions provide for students with disabilities. However, there is little research about the aids and techniques that students with disabilities actually use to meet their course requirements. This thesis explores the way in which students with occupational overuse syndrome (OOS) conditions managed their studies at Victoria University of Wellington. My methodology was influenced by the theoretical principles of emancipatory research, which emphasises a collaborative research process for the purpose of individual and social change. I interviewed thirteen Victoria University students about their OOS condition, their study strategies, and the ways in which this University could make it easier for students with OOS to manage their studies. Generally the participants used aids and techniques to enable themselves to demonstrate their ability to meet their course requirements. They also benefited from Victoria University's efforts to provide an inclusive learning environment for students with disabilities. There were however, weaknesses in some of the support services that are available for students with OOS conditions at this University. Moreover, my findings suggested that attitudinal barriers might prevent some students with OOS conditions from seeking assistance with managing their studies. My goal was to enable students with OOS conditions to demonstrate their abilities, by sharing information about the strategies that some of these students used to manage their studies without aggravating their OOS symptoms, and by recommending changes to Victoria University's policies and practices