scholarly journals Aerodynamic performance of flying discs

2018 ◽  
Vol 90 (2) ◽  
pp. 390-397
Author(s):  
Noorfazreena Kamaruddin ◽  
Jonathan Potts ◽  
William Crowther
Keyword(s):  
Design Methodology ◽  
Aerodynamic Characteristics ◽  
Design Parameters ◽  
Flight Performance ◽  
Content Type ◽  
Six Degree Of Freedom ◽  
Design Factors ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Practical Implications

Purpose The purpose of this paper is to examine geometrical design influence of various types of flying discs on their flight performance from the aerodynamics perspective. Design/methodology/approach The lift, drag and moment coefficients of the discs were measured experimentally using a wind tunnel. Three types of golf discs and four sets of simpler parametric discs were studied to analyze and isolate the effect of design factors on these aerodynamic characteristics. Full six degree-of-freedom simulations of the discs were performed to visualize their flight trajectories and attitudes. These simulations, combined with the experimental data, provide details on the well-known “S-shaped” ground-path traced by a flying disc. Findings This paper reveals two key parameters to evaluate the flight performance of a disc: its coefficient of lift-to-drag ratio (CL/CD) and, more importantly, its coefficient of pitching moment (CM). The latter influences the tendency of the disc to yaw from its intended path, and the former influences its throwing distance. Practical implications The work suggests that to optimize the flight performance of a disc, the magnitudes and gradient of its CM should be minimized and its trim-point shifted from origin, while its CL/CD should be maximized with a flatter peak. Originality/value In this paper, the design parameters and the aerodynamic characteristics of various types of flying discs are analysed, compared and discussed in depth. Recommendations of design improvements to enhance the performance of any flying disc are offered as well.

Development of a 3D printing method for the textile hybrid structure

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jihye Deborah Kang ◽  
Sungmin Kim
Keyword(s):  
3D Printing ◽  
Design Methodology ◽  
Hybrid Structure ◽  
Design Parameters ◽  
Support Structures ◽  
Content Type ◽  
3D Printed ◽  
Curved Panels ◽  
Practical Implications ◽  
Printing Method

PurposeThe development of a 3D printing method for the textile hybrid structure that can both be a solution to the conventional drawbacks of 3D printing method and a step forward to a garment making industry.Design/methodology/approachA novel 3D printing method using the textile hybrid structure was developed to generate 3D object without support structures.Findings3D printing of curved panels without support structure was possible by using fabric tension and residual stress.Practical implicationsGarment panels can be 3D printed without support structures by utilizing the idea of textile hybrid structure. Garment panels are expected to be modelled and printed easily using the Garment Panel Printer (GPP) software developed in this study.Social implications3D printing method developed in the study is expected to reduce the time and material previously needed for support structures.Originality/valueComprehensive preparatory experiments were made to determine the design parameters. Various experiments were designed to test the feasibility and validity of proposed method.

Design parameters improvement of helicopter ducted tail rotor

2018 ◽  
Vol 90 (2) ◽  
pp. 237-245
Author(s):  
Guo Zhong ◽  
Jun Huang ◽  
Mingxu Yi
Keyword(s):  
Noise Reduction ◽  
Design Methodology ◽  
Acoustic Noise ◽  
Prediction Method ◽  
Design Parameters ◽  
Thin Body ◽  
Content Type ◽  
Acoustic Performance ◽  
Body Boundary ◽  
Practical Implications

Purpose The purpose of this paper is to reduce the acoustic noise of helicopter ducted tail rotor. Design/methodology/approach To predict the noise accurately, a thin-body boundary element method (BEM)/Ffowcs Williams–Hawkings method is developed in this paper. It is a hybrid method combining the BEM with computational aeroacoustics and can be used efficiently to predict the propagation of sound wave in the duct. Findings Compared with the experimental results, the proposed method of acoustic noise is rather desirable. Practical implications Then several geometry parameters are modified to investigate the noise reduction of ducted tail rotor by using the numerical prediction method. Originality/value The aerodynamic and acoustic performance of different modification tasks is discussed. These results demonstrate the validity of design parameters modification of ducted tail rotor in acoustic noise reduction.

The influence of localized mechanical stresses on the non-homogeneous distribution of electrical conductivity

2016 ◽  
Vol 35 (6) ◽  
pp. 1983-1995 ◽  
Author(s):  
Ewa Napieralska-Juszczak ◽  
Piotr Napieralski ◽  
Krzysztof Komeza ◽  
Youcef Zeroukhi
Keyword(s):  
Electrical Conductivity ◽  
Design Methodology ◽  
Simulation Method ◽  
Uneven Distribution ◽  
Design Parameters ◽  
Homogeneous Distribution ◽  
Physical Parameters ◽  
Total Resistance ◽  
Content Type ◽  
Practical Implications

Purpose The purpose of this paper is to determine the physical design parameters that influence the total resistance of a twisted conductor (cable). One of the physical parameters characterizing this type of structures is the uneven distribution of resistivity due to hardening, which is the result of stress exerted on the wires during the manufacturing process. Design/methodology/approach The authors have developed a method to take into account the effect of localized hardening on the inhomogeneous distribution of electrical conductivity in the distorted structures of the conductor. To achieve this goal, the authors have implemented a mechanical-electrical simulation method. The resistance characteristics have been measured as a function of mechanical stress. Findings As demonstrated by the results of measurements conducted on various samples and with various cable design parameters, the resistance of a given material (copper or aluminum), expressed as a function of stress, does not depend on the type of force applied. Therefore, the same characteristics may be applied to various cable designs. Practical implications The method presented in this paper enables more detailed investigation of the influence of particular design parameters on the total resistance of a cable. It also provides the ability to determine optimal settings of design parameters. Originality/value The approach is distinct from similar studies because it takes into account the deformed geometry of the conductor and the uneven distribution of the resistivity within a filament. In the literature, it is sometimes stated that the distribution of resistivity in a compacted cable is uneven, but its measurement is deemed impossible. This paper provides a method for determining such a distribution.

Structural dynamics of a gyrocopter: numerical approach in some emergency cases

2018 ◽  
Vol 90 (4) ◽  
pp. 699-710
Author(s):  
Adam Dacko ◽  
Pawel Borkowski ◽  
Lukasz Pawel Lindstedt ◽  
Cezary Rzymkowski ◽  
Miroslaw Rodzewicz
Keyword(s):  
Design Methodology ◽  
Structural Response ◽  
Numerical Approach ◽  
Design Parameters ◽  
Dynamic Problems ◽  
Content Type ◽  
Modeling And Analysis ◽  
Dynamic Events ◽  
Rescue System ◽  
Practical Implications

Purpose This paper aims to present the assumptions, analysis and sample results of numerical modeling and analysis of dynamic events encountered in emergency cases during deployment of parachute rescue system (PRS) and hard landing of a small gyrocopter. The optimal design requires knowledge of structural loads and structural response – the information obtained often from experiment. Numerical simulation is presented as an alternative tool for estimating these data. Design/methodology/approach Structural analyses were performed using MSC.Nastran. Multibody simulations were done using MADYMO system. Findings Initial design parameters were evaluated and verified in numerical simulations. Some of the resulting conclusions were proven during the test flights. Practical implications Some chosen results of simulation of dynamic problems are presented. They can be useful as reference values for similar cases for light aircraft analysis. Originality/value The paper presents an alternative way of assessing structural response parameters in the case of emergency dynamic events of usage of PRS. The results can be used in other projects.

Aerodynamic performance improvement of a canard control missile

2017 ◽  
Vol 89 (6) ◽  
pp. 871-878 ◽  
Author(s):  
M. Tahani ◽  
M. Masdari ◽  
M. Kazemi
Keyword(s):  
Aspect Ratio ◽  
Drag Coefficient ◽  
Cross Section ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Slender Body Theory ◽  
Content Type ◽  
Drag Ratio ◽  
Body Theory ◽  
Lift To Drag Ratio

Purpose This paper aims to analyze the influence of the changings in geometrical parameters on the aerodynamic performance of the control canard projectiles. Design/methodology/approach Because of the mentioned point, the range of projectiles increment has a considerable importance, and the design algorithm of a control canard projectile was first written. Then, were studied the effects of canard geometric parameters such as aspect ratio, taper ratio and deflectable nose on lift to drag coefficient ratio, static margin based on the slender body theory and cross section flow. Findings The code results show that aspect ratio increment, results in an increase in lift-to-drag ratio of the missile, but increase in canard taper ratio results in increasing of lift-to-drag ratio at 1° angle of attack, while during increasing the canard taper ratio up to 0.67 at 4° angle of attack, lift to drag first reaches to maximum and then decreases. Also, static margin decreases with canard taper ratio and aspect ratio increment. The developed results for this type of missile were compared with same experimental and computational fluid dynamic (CFD) results and appreciated agreement with other results at angles of attack between 0° and 6°. Practical implications To design a control canard missile, the effect of each geometric parameter of canard needs to be estimated. For this purpose, the suitable algorithm is used. In this paper, the effects of canard geometric parameters, such as aspect ratio, taper ratio and deflectable nose on lift-to-drag coefficient ratio and static margin, were studied with help of the slender body theory and cross-section flow. Originality/value The contribution of this paper is to predict the aerodynamic characteristics for the control canard missile. In this study, the effect of the design parameter on aerodynamic characteristics can be estimated, and the effect of geometrical characteristics has been analyzed with a suitable algorithm. Also, the best lift-to-drag coefficient for the NASA Tandem Control Missile at Mach 1.75 was selected at various angles of attack. The developed results for this type of missile were compared with same experimental and CFD results.

Consumer value creation through WhatsApp use

2019 ◽  
Vol 32 (4) ◽  
pp. 455-471
Author(s):  
Jorge Cruz-Cárdenas ◽  
Jorge Guadalupe-Lanas ◽  
Ekaterina Zabelina ◽  
Andrés Palacio-Fierro ◽  
Margarita Velín-Fárez ◽  
...  
Keyword(s):  
Latin American ◽  
Value Creation ◽  
Emotional Support ◽  
Design Methodology ◽  
Instant Messaging ◽  
Role Performance ◽  
Content Type ◽  
Consumer Value ◽  
Depth Interviews ◽  
Practical Implications

Purpose The purpose of this paper is to understand in-depth how consumers create value in their lives using WhatsApp, the leading mobile instant messaging (MIM) application. Design/methodology/approach The study adopts the perspective of customer-dominant logic (CDL) and uses a qualitative multimethod design involving 3 focus groups and 25 subsequent in-depth interviews. The research setting was Ecuador, a Latin American country. Findings Analysis and interpretation of the participants’ stories made it possible to identify and understand the creation of four types of value: maintaining and strengthening relationships; improving role performance; emotional support; and entertainment and fun. In addition, the present study proposes a conceptual model of consumer value creation as it applies to MIM. Practical implications Understanding the way consumers create value in their lives using MIM is important not only for organizations that offer MIM applications, but also for those companies that develop other applications for mobile phones or for those who wish to use MIM as an electronic word-of-mouth vehicle. Originality/value The current study is one of the first to address the topic of consumer behavior in the use of technologies from the perspective of CDL; this perspective enables an integrated qualitative vision of value creation in which the consumer is the protagonist.

scholarly journals Advantages and potential challenges of data management in e-maintenance

2019 ◽  
Vol 25 (3) ◽  
pp. 378-396 ◽  
Author(s):  
Arian Razmi-Farooji ◽  
Hanna Kropsu-Vehkaperä ◽  
Janne Härkönen ◽  
Harri Haapasalo
Keyword(s):  
Data Management ◽  
Design Methodology ◽  
Management Practices ◽  
Future Research ◽  
Conceptual Approach ◽  
Content Type ◽  
Different Types ◽  
Maintenance Systems ◽  
Industry Leader ◽  
Practical Implications

Purpose The purpose of this paper is twofold: first, to understand data management challenges in e-maintenance systems from a holistically viewpoint through summarizing the earlier scattered research in the field, and second, to present a conceptual approach for addressing these challenges in practice. Design/methodology/approach The study is realized as a combination of a literature review and by the means of analyzing the practices on an industry leader in manufacturing and maintenance services. Findings This research provides a general understanding over data management challenges in e-maintenance and summarizes their associated proposed solutions. In addition, this paper lists and exemplifies different types and sources of data which can be collected in e-maintenance, across different organizational levels. Analyzing the data management practices of an e-maintenance industry leader provides a conceptual approach to address identified challenges in practice. Research limitations/implications Since this paper is based on studying the practices of a single company, it might be limited to generalize the results. Future research topics can focus on each of mentioned data management challenges and also validate the applicability of presented model in other companies and industries. Practical implications Understanding the e-maintenance-related challenges helps maintenance managers and other involved stakeholders in e-maintenance systems to better solve the challenges. Originality/value The so-far literature on e-maintenance has been studied with narrow focus to data and data management in e-maintenance appears as one of the less studied topics in the literature. This research paper contributes to e-maintenance by highlighting the deficiencies of the discussion surrounding the perspectives of data management in e-maintenance by studying all common data management challenges and listing different types of data which need to be acquired in e-maintenance systems.

An exploratory empirical study of whistleblowing and whistleblowers

2020 ◽  
Vol 27 (3) ◽  
pp. 755-770
Author(s):  
Maria Krambia-Kapardis
Keyword(s):  
Statistical Analysis ◽  
Design Methodology ◽  
Research Topic ◽  
Due Date ◽  
Content Type ◽  
Unethical Behaviour ◽  
Eu Member States ◽  
European Directive ◽  
Original Survey ◽  
Practical Implications

Purpose The purpose of this study is to develop a profile of whistleblowers and to determine whether whistleblowing legislation would encourage those individuals to bring to light some illegal or unethical behaviour that otherwise would remain in the shadows. Design/methodology/approach Having identified whistleblowing correlation, a survey was carried out in Cyprus of actual whistleblowers and could-have-been whistleblowers. Findings Males between 46 and55 years of age, regardless of whether they have dependents or hold senior positions in organizations are significantly more likely to blow the whistle. However, could-have-been whistleblowers did not go ahead because they felt that the authorities would not act on their information. Research limitations/implications Because of the sensitive nature of the research topic and the fact that only whistleblowers or intended whistleblowers could participate in the study, the sample size is limited as a result. This, in turn, limits both the number of respondents in each category (actual and intended) as well as constrains the statistical analysis that could be carried out on the data. Practical implications It remains to be seen whether EU Member States shall implement the European Directive 2019/1937 on the protection of persons who report breaches of Union Law, in its entirety by the due date, namely December 2021. Originality/value This study provides a literature review of whistleblowing and reports an original survey against the backdrop of the European Directive.

How Phillips saw the light

2020 ◽  
Vol 36 (8) ◽  
pp. 29-31
Keyword(s):  
Design Methodology ◽  
Reading Time ◽  
Daily Basis ◽  
Business World ◽  
Content Type ◽  
Freak Show ◽  
The World ◽  
Pertinent Information ◽  
The One ◽  
Practical Implications

Purpose Reviews the latest management developments across the globe and pinpoints practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings The problem with developing a reputation of being something of an oracle in the business world is that all of a sudden, everyone expects you to pull off the trick of interpreting the future on a daily basis. Like a freak show circus act or one-hit wonder pop singer, people expect you to perform when they see you, and they expect you to perform the thing that made you famous, even if it is the one thing in the world you don’t want to do. And when you fail to deliver on these heightened expectations, you are dismissed as a one trick pony, however good that trick is in the first place. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

scholarly journals Examining the accounts of oil spills crises in Nigeria through sensegiving and defensive behaviours

2020 ◽  
Vol 33 (8) ◽  
pp. 2053-2076 ◽  
Author(s):  
Osamuyimen Egbon ◽  
Chijoke Oscar Mgbame
Keyword(s):  
Policy Implication ◽  
Design Methodology ◽  
Oil Spills ◽  
Burden Of Proof ◽  
Multinational Companies ◽  
External Factors ◽  
Content Type ◽  
Political Dynamics ◽  
Defensive Behaviours ◽  
Practical Implications

PurposeThe paper examines how oil multinational companies (MNCs) in Nigeria framed accounts to dissociate themselves from causing oil spills.Design/methodology/approachThe authors utilised data from relevant corporate reports, external accounts and interviews, and used sensegiving with defensive behaviours theoretical framing to explore corporate narratives aimed at altering stakeholders' perceptions.FindingsThe corporations gave sense to their audience by invoking scapegoating blame avoidance narrative in attributing the cause of most oil spills in Nigeria to outsiders (sabotage), despite potentially misclassifying the sabotage-corrosion dichotomy. Corporate stance was reinforced through justifying narrative, which suggested that multi-stakeholders jointly determined the causes of oil spills, thus portraying corporate accounts as transparent, credible and objective.Research limitations/implicationsThe socio-political dynamics in an empirical setting affect corporate accounts and how those accounts appear persuasive, implying that such contextual factors merit consideration when evaluating corporate accounts. For example, despite contradictions in corporate accounts, corporate attribution of oil spills to external factors appeared persuasive due to the inherently complicated socio-political dynamics.Practical implicationsWith compensation to oil spills' victims only legally permitted for non-sabotage-induced spills alongside the burden of proof on the victims, the MNCs are incentivised to attribute most oil spills to sabotage. On policy implication, accountability would be best served when the MNCs are tasked both with the burden of proof and a responsibility to demonstrate their transparency in preventing oil spills, including those caused by sabotage.Originality/valueCrisis situations generate multiple and competing perspectives, but sensegiving and defensive behaviours lenses enrich our understanding of how crisis-ridden companies frame narratives to alter stakeholders' perceptions. Accounts-giving therefore partly satisfies accountability demands, and acts as sensegiving signals aimed at reframing/redefining existing perceptions.

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