Lift force reduction due to body image of vortex for a hovering flight model

2012 ◽  
Vol 709 ◽  
pp. 648-658 ◽  
Author(s):  
X. X. Wang ◽  
Z. N. Wu
Keyword(s):  
Body Image ◽  
Body Size ◽  
Lift Force ◽  
The Body ◽  
Vortex Rings ◽  
Body Images ◽  
Hovering Flight ◽  
Equivalent Radius ◽  
Force Reduction ◽  
Relative Body Size

AbstractThe effect of the body on the lift force in hovering flight is studied here by including the effect of image vortex rings (IVRs) in the inviscid vortex ring model proposed by Rayner (J. Fluid Mech., vol. 91, 1979, pp. 697–730) and used by Wang & Wu (J. Fluid Mech., vol. 654, 2010, pp. 453–472) to study lift force due to wakes. The body is treated simply as an equivalent sphere following the data of Ellington (Phil. Trans. R. Soc. Lond. B, vol. 305, 1984a, pp. 17–40). It is shown that the body image reduces the lift by inducing a further downwash near the wing tip and an additional contraction to the real vortex rings (RVRs). The amount of force reduction due to body image is found to grow cubically with relative body size, defined by the equivalent radius relative to the wing span, and approximately linearly with the feathering parameter. For Apis and Bombus with large relative body size and large feathering parameter, the body images reduce lift by an amount near 8 % according to the present simplified analysis.

scholarly journals Visual body size adaptation and estimation of tactile distance

2020 ◽  
Author(s):  
Regine Zopf ◽  
Veronika Kosourikhina ◽  
Kevin R. Brooks ◽  
Vince Polito ◽  
Ian Stephen
Keyword(s):  
Body Size ◽  
Adaptation Effect ◽  
The Body ◽  
Size Perception ◽  
Visual Adaptation ◽  
Social Environments ◽  
Body Images ◽  
Tactile Stimuli ◽  
Before And After ◽  
Adaptation Effects

Estimating the size of bodies is crucial for interactions with physical and social environments. Body size perception is malleable and can be altered using visual adaptation paradigms. However, it is unclear whether such visual adaptation effects also transfer to other modalities and influence, for example, the perception of tactile distances. In this study we employed a visual adaptation paradigm. Participants were exposed to images of expanded or contracted versions of self- or other-identity bodies. Before and after this adaptation they were asked to manipulate the width of body images to appear as “normal” as possible. We replicated an effect of visual adaptation, such that the body size selected as most “normal” was larger after exposure to expanded and thinner after exposure to contracted adaptation stimuli. In contrast, we did not find evidence that this adaptation effect transfers to distance estimates for paired tactile stimuli delivered to the abdomen. A Bayesian analysis showed that our data provide moderate evidence that there is no effect of visual body size adaptation on the estimation of spatial parameters in a tactile task. This suggests that visual body size adaptation effects do not transfer to somatosensory body size representations.

scholarly journals Perception of Body Image and Dietary Habit Among Adults Aged 20–45 Years at Sunyani Metropolis

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 277-277
Author(s):  
Jacob Setorglo ◽  
Philip Narteh Gorleku ◽  
Kyei Roselyn ◽  
Kingsley Kwadwo Asare Pereko
Keyword(s):  
Body Mass Index ◽  
Body Image ◽  
Body Size ◽  
Body Mass ◽  
Who Classification ◽  
The Body ◽  
World Health ◽  
Outcome Variable ◽  
Sugar Consumption ◽  
Normal Body

Abstract Objectives The study assessed the body size perception of respondents against the WHO body mass index and related the body sizes to fat and sugar consumption among 20–45-year-old adults. Methods The study design was a descriptive cross-sectional survey which involved 200 respondents aged 20–45 years, sampled conveniently. at Sunyani. Data on socio-demographic, fat and sugar consumption, anthropometry (weight in kg, height in cm) were collected. The weight and height data were later converted into body mass index using the World Health Organisation (WHO) classification. Sugar and fat intakes were measured by dietary food based assessment. (Analysis was done using IBM SPSS version 25. Proportions were presented for categorical values. Chi square test of association was used to determine relationship between the independent and the dependent outcome variable. Statistical significant was set at and P < 0.05. Results The mean age of the respondents was 35 years. About 35.0% of respondents were males and the rest 65.0% females. Sugar and fat consumption among the respondents were within the recommended dietary allowances. Although 75% of respondents had normal body mass index (kg/m2) and 21% were obese based on the WHO classification, Majority (43.0%) of them perceived their body weights were normal. About 48.1% perceived they are either obese or had normal body size. There was no statistically significant association between respondents’ perceived body image and socio-demographic characteristics except for marital status (X2 = 8.82, P = 0.044). There was no statistically significant association between body image perception and dietary intake of fat and sugar. Conclusions There is great disparity in the perception of respondents body image compared to the WHO classification and married women and men are more particular about how they look. Dietary components studied do not have any association with body image. Funding Sources None.

Body-Size Estimation in Anorexia Nervosa

1995 ◽  
Vol 81 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Enrico Molinari
Keyword(s):  
Body Image ◽  
Anorexia Nervosa ◽  
Body Size ◽  
The Body ◽  
Control Group ◽  
Size Estimation ◽  
Image Perception ◽  
Pelvic Area ◽  
Body Size Estimation ◽  
Different Parts

The aim was to explore the body-image perception of a group of 20 hospitalised anorexic patients, aged 18 to 21 years, undergoing a period of treatment. The instrument used was the Askevold nonverbal perception test as modified by Allamani and colleagues in 1978 to assess perception of the dimensions of different parts of the body by exploiting the capacity to project them into space. The four parts were the head, the thoracic area, the abdominal area, and the pelvic area. Analysis of responses indicated that anorexic patients overestimated the abdominal and the pelvic areas much more than the 20 members of the control group (50% vs 30%). The areas of the head and thorax were perceived almost in their real dimensions by the anorexic patients but were underestimated by the control group.

scholarly journals Level of Physical Activity on the Body Image of Young Women

2019 ◽  
Vol 36 (03) ◽  
pp. 156-161
Author(s):  
Katielly Santana ◽  
Almir de França Ferraz ◽  
André Rodrigues Lourenço Dias ◽  
Rosilene Andrade Silva Rodrigues ◽  
Camila Pasa ◽  
...  
Keyword(s):  
Physical Activity ◽  
Body Image ◽  
Body Image Dissatisfaction ◽  
The Body ◽  
Lower Amount ◽  
Body Images ◽  
Education Professionals ◽  
Vigorous Intensity ◽  
Different Levels ◽  
Activity Questionnaire

AbstractPhysical exercise has the ability to alter the measurements of the body related to esthetic. The objective of the present study was to compare the body image and body esthetic between two groups of women with different levels of physical activity. We evaluated 79 women who were divided into 2 groups: 39 women with low or moderate levels of physical activity, and 40 women with high levels of physical activity according to the International Physical Activity Questionnaire (IPAQ). Anthropometric and body composition measurements were taken using the InBody S10 multifrequency device (InBody Co., Eonju-ro, Gangnam-gu, Seoul, South Korea). The scale of silhouettes, which is composed of 9 engravings of body images, was used to verify the body image, as well as the Portuguese version of the Body Shape Questionnaire (BSQ) validated for university students. The group of evaluators was composed of twenty physical education professionals of both sexes, ten male and ten female. The group with low/moderate levels of physical activity, as expected, showed a lower amount (minutes per week) of physical activity of mild, moderate and vigorous intensity when compared with the group with high levels of physical activity (p < 0.05), and they also had a higher ratio of fat mass (FM) per height squared (p = 0.047). The BSQ questionnaire scores, the current and ideal silhouettes, as well as body image dissatisfaction, were not different between the groups (p > 0.05). The overall body esthetic score, attributed only by the male and only by the female evaluators, did not differ significantly (p > 0.05). We concluded that the level of physical activity did not influence the body image and body esthetic of the women.

Can Health and Wellbeing Come in All Shapes and Sizes? Dieting: The Big Con. A Harm Minimisation Program

2002 ◽  
Vol 8 (2) ◽  
pp. 39
Author(s):  
Susan Mann ◽  
Helen Harmer
Keyword(s):  
Body Image ◽  
Body Size ◽  
Healthy Lifestyle ◽  
The Body ◽  
Health Promotion Program ◽  
Harm Minimisation ◽  
Size And Shape ◽  
Community Health Nurses ◽  
Ideal Body Image ◽  
The Media

Stress, low self-esteem, mental illness issues and physical debility are recognised outcomes for women striving for an ideal body image (Paxton 2000). However, the prevailing discourse remains that healthy lifestyle relates to specific body size and shape. This message is evident throughout the media, which clearly links healthy people to slim bodies imbued with youth, vitality and good looks. Community health nurses, concerned for women in the community who were deemed overweight by the Body Mass Index scale and engaged in cyclic patterns of dieting, initiated a health promotion program, aimed at challenging such discourse. A multidisciplinary group involving expertise from nursing, nutrition, psychology and community members was established to develop and run a program for women, which focused on body image, healthy lifestyles and eating patterns. This paper discusses the outcomes of these programs, which challenge the argument that body size and shape determines health.

Aerodynamics of a half-rotating wing in hovering flight: An integrated study

2021 ◽  
pp. 095441002199654
Author(s):  
Qian Li ◽  
Jiwei Yuan ◽  
Huan Shen ◽  
Jiaguo Deng ◽  
Timothy R Jakobi ◽  
...  
Keyword(s):  
Flow Field ◽  
Vortex Ring ◽  
Lift Force ◽  
Computational Models ◽  
Lift Coefficient ◽  
The Body ◽  
Driving Mechanism ◽  
Hovering Flight ◽  
Flexible Wing ◽  
Rotating Wing

This study introduces a new quasi-flapping wing driving mechanism based on a half-rotating mechanism which is capable of pure rotational flapping rather than the more traditional oscillatory flapping method. Lift models for half-rotating wing (HRW) aircraft in hovering flight are proposed based on the kinematics of a HRW prototype and the flow characteristics near the surface of its wing. Alongside further analytical expressions for lift based on kinematic extractions, computational models and a novel lift validation mechanism are used to reinforce the aerodynamic characteristics of the HRW in hovering flight. The aerodynamics of the HRW are experimentally assessed for different wing layouts and wing materials. Results indicate that the flow field generated by the motion of the wing arranged symmetrically on both sides of the body interfere with each other, causing the average lift coefficient of the paired-wing HRW to be less than that of the single-wing HRW. The average lift coefficient of the flexible wing is larger than that of the rigid wing. In addition, the average lift of the flexible wing increases with increasing flexural compliance within a particular range. Lift forces in different flight conditions are calculated using derived formulas alongside representative computational models, through which the derivation of lift variation for the HRW in hovering flight is validated. The theoretical lift curves show reasonable agreement with numerical simulation results in terms of the time course over one stroke cycle. The mechanisms of the HRW for generation and shedding of vortices in hovering flight are further revealed in computed flow field characteristics results. The velocity vectors of the flow field between the HRW and the symmetrically rotating wing indicate that the HRW with asymmetric rotation can generate lift force effectively. The velocity difference between the wing and the fluid is the key factor influencing the structure of generated vortices. In detailed three-dimensional (3D) vortex flows, our computational fluid dynamics study shows that a horseshoe-shaped vortex is first generated in the early downstroke. The horseshoe-shaped vortex subsequently grows into a doughnut-shaped vortex ring, with a jet stream appearing in its core which forms the downwash. The doughnut-shaped vortex ring eventually elongates into a long arc-shaped wake vortex ring. A large increasing lift force is generated during the upstroke, most likely due to the stable distal attached vortices; and in accordance with this, downwash becomes evident in the vortex ring during the downstroke.

scholarly journals Representation of youth body images in Hilo Teen advertising (Norman Fairclough critical discourse analysis)

2019 ◽  
Vol 2 (2) ◽  
pp. 127-138
Author(s):  
Hanna Sundari ◽  
Rina Husnaini Febriyanti
Keyword(s):  
Body Image ◽  
Discourse Analysis ◽  
Critical Discourse Analysis ◽  
Social Practice ◽  
The Body ◽  
Critical Discourse ◽  
Physical Aspect ◽  
Milk Product ◽  
Body Images ◽  
Teenage Girls

This research is conducted using model of Critical Discourse Analysis (CDA) that stated by Norman Fairclough. This discourse analysis is selected because it is considered to be able to answer the question of the purpose of this research that is formulated which focused on digging up the ideology value on teenager body image that is displayed on the discourse analysis in Hilo Teen advertisement. Fairclough sees a discourse as a social practice and authority which involves particular ideology value whether in explicitly or implicitly. The analysis of Fairclough is centered on text, discourse practice, and sociocultural practice. In this research, discourse analysis text Hilo Teen advertisement is focused on text dimension that involves representation, relation, and identity that is aired on the advertisement and sociocultural context in community scope. The result of this research based on the analysis defines Hilo Teen advertisement describes the body image of teenage girls are thin, slim, tall, and energetic; on the other hand, the body image of teenage boys are thin and tall. This advertisement also displays the problematic and realistic of teenagers who accentuate physical aspect only. Furthermore, Hilo Teen advertisement not only promotes milk product for teenagers but also tries forming a perception and conception on the society (teenagers and parents) about an ideal body shape of teenagers.

scholarly journals CHARACTERISTICS OF BODY IMAGE IN TEENAGE GIRLS ENGAGED IN FIGURE SKATING

2018 ◽  
pp. 147-152
Author(s):  
I. S. Morozova ◽  
K. N. Belogai ◽  
E. S. Kagan
Keyword(s):  
Body Image ◽  
The Body ◽  
The Self ◽  
Control Group ◽  
Figure Skating ◽  
Functional Characteristics ◽  
Body Images ◽  
Correlation Matrices ◽  
Teenage Girls ◽  
Content Characteristics

The paper features the results of the study of the body image content characteristics in adolescent girls. The empirical study involved 12–14 year-old girls engaged in figure skating, and those not engaged in sports. The body image analysis was based on questionnaires and projective methods. It has been revealed that the content characteristics of the body image are interrelated with the parameters of self-relationship and self-esteem, regardless of whether the girl is engaged in sports or not. At the same time, athletes mostly appreciate the functional characteristics of the body, i.e. its activity and strength, whereas the girls in the control group assess their appearance. The gap between the real and the ideal body images appears to be higher in athletes. Comparison of the correlation matrices in the two groups shows that, in the group of athletes, the self-relationship parameters are correlated with the body evaluation, the evaluation of its strength, activity and functional characteristics. In the control group, the self-relationship parameters are related both to the functional characteristics of the body and to the appearance evaluation.

scholarly journals Fatness and Failing Citizenship

Somatechnics ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 218-233 ◽  
Author(s):  
Jen Rinaldi ◽  
Carla Rice ◽  
Andrea LaMarre ◽  
Deborah McPhail ◽  
Elisabeth Harrison
Keyword(s):  
Body Image ◽  
Body Size ◽  
The Body ◽  
Sexual Citizenship ◽  
Research Project ◽  
Queer Space ◽  
Queer Communities ◽  
Body Image Ideals ◽  
Management Expectations ◽  
Depth Interviews

This article examines how queer persons negotiate the technologies of health deployed to shape sexual citizenship, especially in relation to body size. Beginning with the claim that fatness is always already queered, the authors bring Jasbir Puar's concept of homonationalism into conversation with Samantha Murray's argument that fat persons are positioned as failed citizens. The authors illustrate how fat embodied subjects confront problematics of belonging through analysing in-depth interviews conducted for a research project that investigated how members of queer communities come up against, are affected by and resist body image ideals and body management expectations. Interview excerpts are organised around sites of constraint, contestation and creativity: medical space, queer space and the body as space.

scholarly journals Imagem corporal e indicadores antropométricos em adolescentes vivendo com HIV

2018 ◽  
Vol 20 (1) ◽  
pp. 53-63
Author(s):  
Luiz Rodrigo Augustemak de Lima ◽  
Davi Monteiro Teixeira ◽  
Priscila Custódio Martins ◽  
Cilene Rebolho Martins ◽  
Andreia Pelegrini ◽  
...  
Keyword(s):  
Body Image ◽  
Body Weight ◽  
Body Size ◽  
Body Image Dissatisfaction ◽  
The Body ◽  
Control Group ◽  
Muscle Area ◽  
Anthropometric Indicators ◽  
Point Body ◽  
Living With Hiv

The aim of this study was to compare body image and anthropometric indicators among adolescents living with HIV and healthy adolescents (control group). In addition, we verified the associations of anthropometric indicators, infection/treatment, sexual maturity, and sociodemographic characteristics with body image in adolescents living with HIV. One hundred and eleven adolescents aged 10 to 15 years were divided into those living with HIV (n = 57) and a control group (n = 54). Body image was investigated using an eight-point body silhouette scale. Body weight, height, circumferences, and skinfolds were measured. Body image dissatisfaction was found in 54.4% of the adolescents living with HIV, with 38.6% of them wishing to increase their body size. Conversely, body image dissatisfaction was due to the desire to reduce body size in the control group (40.7%). No difference between the HIV and control groups was found for the anthropometric indicators analyzed. Gender (β = -0.52), age (β = 0.18), body weight (β = 0.07), body mass index (β = -0.19), and upper arm muscle area (β = -0.08) explained 42% of the variation in the body image score of adolescents living with HIV. Thinness is the main reason for body image dissatisfaction in adolescents living with HIV. Almost half the body dissatisfaction of adolescents living with HIV was explained by demographic and anthropometric variables. 

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