Design improvement of air deployable parachute for high altitude launch ofpayload based on investigationand experimentation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mahendra Pratap ◽  
Anil Kumar Agrawal ◽  
Subhash Chandra Sati ◽  
Arun Kumar Saxena
Keyword(s):  
High Altitude ◽  
Theoretical Investigation ◽  
Design Methodology ◽  
Cfd Analysis ◽  
Flight Tests ◽  
Content Type ◽  
Design Changes ◽  
Canopy Area ◽  
Theoretical Investigations ◽  
Computational Fluid Dynamics Cfd

Purpose The purpose of this paper is to improve the design of a solid square canopy of a parachute. The design improvements are brought out by providing minor slits in the canopy area. Proper designing of the parachute was carried out using theoretical investigation coupled with experimentation. This parachute is designed for launch of sonobuoy from fixed wing aircraft. Design/methodology/approach Literature review was carried out on the design of such parachutes for the launch of a sonobuoy from a high altitude to the water entry. Computational fluid dynamics (CFD) analysis provided the value of the coefficient of drag for the slit-cut square canopy parachute, with and without sonobuoy for different lengths of the slit. Besides the theoretical investigation, experimentation was also carried out to validate the design. Findings The experimentation was carried out on 58 and 75 gsm fabric canopies with the slit edge plain-cut with thermally sealed edges, stitched and strengthened. In the case of plain-cut slits on the canopy made of 75 gsm fabric, no tearing of the slit edge was observed in dynamic and flight tests. Research limitations/implications The present work has been carried out considering various assumptions and limited trial data specific to precision drop of 9 kg payload. The work can be adopted for bigger parachute for dropping of higher payloads. Originality/value Lab strength test, track dynamic and flight trials were conducted to acquire useful data for the present analysis. Besides the theoretical investigations and CFD analysis inherently based on numerous assumptions, experimentation was carried out as the sonobuoy deployment conditions are full of uncertainty. Dynamic and airdrop tests were conducted for this reason to determine design changes in the slits, both at the material level and on improvisations.

Employing needs-based funding formulae – some unavoidable tradeoffs

2017 ◽  
Vol 31 (7) ◽  
pp. 1092-1102
Author(s):  
Tal Gilead ◽  
Iris BenDavid-Hadar
Keyword(s):  
Decision Making ◽  
Resource Allocation ◽  
Design Methodology ◽  
Social Equity ◽  
School Resources ◽  
Content Type ◽  
Funding Formula ◽  
Policy Goals ◽  
Theoretical Investigations ◽  
Schooling System

Purpose The method by which the state allocates resources to its schooling system can serve as an important instrument for achieving desired improvements in levels of educational attainment, social equity and other social policy goals. In many school systems, the allocation of school resources is done according to a needs-based funding formula. The purpose of this paper is to provide a deeper understanding of some significant tradeoffs involved in employing needs-based funding formulae. Design/methodology/approach The paper is based on theoretical investigations of normative aspects involved in using needs-based funding formulae. Findings There are a number of underexplored complications and difficulties that arise from the use of needs-based funding formulae. Dealing with these involves significant tradeoffs that require taking normative decisions. Understanding these tradeoffs is important for improving the use of needs-based funding formulae. Originality/value The paper highlights three under-examined issues that emerge from the current use of needs-based funding formulae. These issues are: to what extent funding formulae should be responsive to social and economic needs? To what extent should funding formulae allow for the use of discretion in resource allocation? To what degree needs-based formulae funding should be linked to outcomes? By discussing these issues and the tradeoffs involved in them, the paper provides a deeper understanding of significant aspects stemming from the use of needs-based funding formulae. This, in turn, can serve as a basis for an improved and better informed process for decision making regarding the use of funding formulae.

Numerical evaluation of separation efficiency in the diverging T-junction for slug flow

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Faheem Ejaz ◽  
William Pao ◽  
Hafiz Muhammad Ali
Keyword(s):  
Slug Flow ◽  
Design Methodology ◽  
Separation Efficiency ◽  
Fluid Model ◽  
Diameter Ratio ◽  
Maintenance Costs ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Practical Implications ◽  
High Separation

Purpose Offshore industries encounter severe production downtime due to high liquid carryovers in the T-junction. The diameter ratio and flow regime can significantly affect the excess liquid carryovers. Unfortunately, regular and reduce T-junctions have low separation efficiencies. Ansys as a commercial computational fluid dynamics (CFD) software was used to model and numerically inspect a novel diverging T-junction design. The purpose of diverging T-junction is to merge the specific characteristics of regular and reduced T-junctions, ultimately increasing separation efficiency. The purpose of this study is to numerically compute the separation efficiency for five distinct diverging T-junctions for eight different velocity ratios. The results were compared to regular and converging T-junctions. Design/methodology/approach Air-water slug flow was simulated with the help of the volume of the fluid model, coupled with the K-epsilon turbulence model to track liquid-gas interfaces. Findings The results of this study indicated that T-junctions with upstream and downstream diameter ratio combinations of 0.8–1 and 0.5–1 achieved separation efficiency of 96% and 94.5%, respectively. These two diverging T-junctions had significantly higher separation efficiencies when compared to regular and converging T-junctions. Results also revealed that over-reduction of upstream and downstream diameter ratios below 0.5 and 1, respectively, lead to declination in separation efficiency. Research limitations/implications The present study is constrained for air and water as working fluids. Nevertheless, the results apply to other applications as well. Practical implications The proposed T-junction is intended to reduce excessive liquid carryovers and frequent plant shutdowns. Thus, lowering operational costs and enhancing separation efficiency. Social implications Higher separation efficiency achieved by using diverging T-junction enabled reduced production downtimes and resulted in lower maintenance costs. Originality/value A novel T-junction design was proposed in this study with a separation efficiency of higher than 90%. High separation efficiency eliminates loss of time during shutdowns and lowers maintenance costs. Furthermore, limitations of this study were also addressed as the lower upstream and downstream diameter ratio does not always enhance separation efficiency.

Combination of experiments and CFD analysis for in-flight wings deflections estimation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamid Reza Ovesy ◽  
Ali Gharibi ◽  
Reza Khaki
Keyword(s):  
Correlation Method ◽  
Linear Regression Method ◽  
Cfd Analysis ◽  
Concentrated Load ◽  
Flight Tests ◽  
Content Type ◽  
Aerodynamic Loads ◽  
Rear Wing ◽  
Alternative Approach ◽  
Ground Test

Purpose This study aims to develop a new correlation method for prediction of in-flight wings deflections by integration of the experimental ground tests with computational fluid dynamics (CFD) analysis. Design/methodology/approach The ground test results are implemented in the curve fitting process to determine deflections at 66 specific points (SPs) on the front and rear wing torque box. By using the obtained deflections and the corresponding applied loads, an experimental deflection equation (EDE) for each point is established through the Castigliano’s theorem. The CFD aerodynamic loads of typical aircraft, which have been obtained earlier by the authors, are once again used in the current research. The total applied loads to each part are achieved via summation of inertia and aerodynamic loads. The obtained loads are transformed to the equivalent concentrated loads at the SPs. By substituting the concentrated load values in the EDEs, the SPs deflections are achieved for mentioned flight conditions. The resulted deflections and the corresponding input flight parameters, i.e. M and α, are incorporated into a linear regression method for development of the appropriate in-flight deflection equations (IFDEs). The validity of IFDEs is approved by comparing IFDEs’ deflections with the corresponding ones calculated through EDEs for different flight conditions. Findings As an alternative approach to the fairly expensive flight tests, the IFDEs can be used to predict the in-flight wing deflections with comparable degree of accuracy. Originality/value Prediction of actual wing deflections distributions without flight tests execution at any given flight condition.

New kids on the mall: babyfied dogs as fashionable co-consumers

2014 ◽  
Vol 15 (3) ◽  
pp. 263-272 ◽  
Author(s):  
Annamari Vänskä
Keyword(s):  
Theoretical Investigation ◽  
Design Methodology ◽  
Theme Issue ◽  
Content Type ◽  
Number Of Children ◽  
The Family ◽  
Original Contribution ◽  
The Relationship

Purpose – This article is a theoretical investigation about the babyfied dog and the troubled relationship between dogs and parenting in contemporary consumerist culture. Design/methodology/approach – In the frame of the special theme issue, the focus of the article is on theorising consumption and care in the context of new motherhood. The article analyses why the babyfied and fashionable dog has become so popular and what the human–dog/animal–transgression is about. Findings – The anthropomorphised animal is an integral part of constructing and understanding the romantic ideal of childhood and childhood innocence. Simultaneously with the modern educational attitude towards pets and animals in general, real animals, especially small lapdogs, have started to replace teddy bears and other plush animals as the dressed-up childlike animal. The tamed and designed animal is not completely an animal anymore and occupies the space between the human and the animal, becoming central to the reconfiguration of the family, childhood, leisure and identity. Currently, as the number of children in families decreases, the babyfied dog is taking the place traditionally reserved for the child. Research limitations/implications – Even though the findings cannot be generalised, they suggest that more research on the relationship between humans and dogs is needed. Originality/value – The article makes an original contribution to the theme issue by focusing on the still unusual, yet strongly emerging form of parenting and care of dogs. Doing this, the article challenges ideas about “natural parenting” by arguing that dogs are the latest babies and fashionable co-consumers.

scholarly journals Work-wear pattern design to accommodate different working postures

2017 ◽  
Vol 29 (3) ◽  
pp. 294-313 ◽  
Author(s):  
Sara Bragança ◽  
Miguel Carvalho ◽  
Pedro Arezes ◽  
Susan P. Ashdown
Keyword(s):  
Design Methodology ◽  
Upper Body ◽  
Pattern Design ◽  
Content Type ◽  
Professional Activities ◽  
Design Changes ◽  
Working Postures ◽  
Standard Base ◽  
Practical Implications ◽  
Made In

Purpose This paper presents an analysis of several issues that are preponderant for the work-wear design. The purpose of this paper is to create a prototype of a women’s base upper body garment, based on the information gathered. Design/methodology/approach All the necessary information was collected through questionnaires, anthropometric measurements and evaluation of compression forces between the different prototypes. Findings It was possible to conclude that to create a better design some alterations need to be made in the standard base pattern design, such as measurements across the back length. Research limitations/implications Despite the fact that these design changes have a great impact on the stretch ability and on the compression forces, using softer fabric, such as cotton, is always better for an increased comfort. However, in more professional situation where these fabrics should not be used, these design changes can really make a difference. Practical implications A test with a set of compression sensors showed that the simple alteration of one measurement in the design of the base patterns highly reduces the compression forces. Social implications These simple alterations allow the garments to adjust to the users’ needs, promoting higher levels of comfort and lower levels of limitations of movement. Originality/value The designs presented in this paper can be easily adapted to a variety of garments, such as jackets or dresses, both for leisure or professional activities.

Modelling the effect of computation sampling on insight error in computational fluid dynamics scientific simulation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Moeti Masiane ◽  
Eric Jacques ◽  
Wuchun Feng ◽  
Chris North
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Methodology ◽  
Cfd Simulation ◽  
Grid Resolution ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Independent Variable ◽  
Cfd Applications ◽  
The Ideal

Purpose The purpose of this paper is to collect data from humans as they generate insights from the visualised results of computational fluid dynamics (CFD) scientific simulation. The authors hypothesise the behaviour of their insight errors (IEs) and proceed to quantify the IEs provided by the crowd participants. They then use the insight framework to model the behaviours of the errors. Using the crowd responses and models from the framework, they test the hypotheses and use the results to validate the framework for the speedup of CFD applications. Design/methodology/approach The authors use a randomised between-subjects experiment with blocking. CFD grid resolution is the independent variable while IE is the dependent variable. The experiment has one treatment factor with five levels. In case varying timestamps has an effect on insight variance levels, the authors block the responses by timestep. In total, 150 participants are randomly assigned to one of five groups and also randomly assigned to one of five blocks within a treatment. Participants are asked to complete a benchmark and open-ended task. Findings The authors find that the variances of insight and perception errors have a U-shaped relationship with grid resolution, that similar to the previously studied visualisation applications, the IE framework is valid for insights generated from CFD results and grid resolution can be used to predict the variance of IE resulting from observing CFD post-processing results. Originality/value To the best of the authors’ knowledge, no other work has measured IE variance to present it to simulation users so that they can use it as a feedback metric for selecting the ideal grid resolution when using grid resolution to speedup CFD simulation.

A simplified analytical method for the pressure of tilt hydrostatic journal bearing

2018 ◽  
Vol 70 (6) ◽  
pp. 993-1001 ◽  
Author(s):  
Yikang Du ◽  
Kuanmin Mao ◽  
Hongqi Liu ◽  
Xiaobo Mao ◽  
Zhihang Li
Keyword(s):  
Design Methodology ◽  
Ball Bearing ◽  
Journal Bearing ◽  
Mathematic Model ◽  
Load Force ◽  
Content Type ◽  
Hydrostatic Bearing ◽  
Experimental Apparatus ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

PurposeThis paper aims to present a simplified method to predict the pressure of the recess, no matter whether the tilt center coincides with the geometric center of the hydrostatic journal bearings.Design/methodology/approachTo validate the effectiveness of the presented model, computational fluid dynamics (CFD) method and experimental method are performed in this study.FindingsBy comparing the CFD results and the experimental results, the pressure of the recess is related to the tilt direction, the tilt center, the width of the land and the circumferential angle of the land.Originality/valueThe mathematic model requires equivalent resistance of land edge – tilt position, tilt direction, tilt angle and the thickness of oil film instead of any digital iteration. Furthermore, a novel experimental apparatus including a circular hydrostatic bearing called ball bearing is designed to study the tilt effect produced by manufacturing error and offset load force on the pressure of the recess.

Grammar-based transformations: attack and defence

2014 ◽  
Vol 22 (2) ◽  
pp. 141-154
Author(s):  
Dusan Repel ◽  
Ingo Stengel
Keyword(s):  
Theoretical Investigation ◽  
Frequency Analysis ◽  
Design Methodology ◽  
Empirical Investigation ◽  
Development Environment ◽  
Context Free Grammar ◽  
Content Type ◽  
Context Free ◽  
Context Free Grammars

Purpose – This research aims to propose an attack that de-obfuscates codes by exploiting the properties of context-free grammars since it is important to understand the strength of obfuscation provided by context-free grammar-based obfuscators. In addition, the possibility of automatically generated transformations is explored. Design/methodology/approach – As part of our empirical investigation, a development environment for obfuscating transformations is built. The tool is used to simulate a context-free obfuscator and to devise ways of reversing such transformations. Furthermore, a theoretical investigation of subset grammars and subset languages is carried out. Findings – It is concluded that context-free grammar-based obfuscators provide limited levels of protection. Nevertheless, their application is appropriate when combined with other obfuscating techniques. Research limitations/implications – The algorithms behave as expected on a limited number of test samples. Further work is required to increase their practicality and to establish their average reliability. Originality/value – This research shows how a frequency analysis attack can threaten the security of code scrambled by context-free grammar-based obfuscators.

A review of experimental techniques to predict aircraft spin and recovery characteristics

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bilal Malik ◽  
Jehanzeb Masud ◽  
Suhail Akhtar
Keyword(s):  
Design Methodology ◽  
State Of The Art ◽  
Experimental Techniques ◽  
Dynamic Force ◽  
Free Flight ◽  
Open Problems ◽  
Flight Tests ◽  
Content Type ◽  
Novel Technique ◽  
The Subject

Purpose This paper aims to provide a detailed review of the experimental research on the prediction of aircraft spin and recovery characteristics using dynamically scaled aircraft models. Design/methodology/approach The paper organizes experimental techniques to predict aircraft spin and recovery characteristics into three broad categories: dynamic free-flight tests, dynamic force tests and a relatively novel technique called wind tunnel based virtual flight testing. Findings After a thorough review, usefulness, limitations and open problems in the presented techniques are highlighted to provide a useful reference to researchers. The area of application of each technique within the research scope of aircraft spin is also presented. Originality/value Previous reviews on the prediction of aircraft spin and recovery characteristics were published many years ago and also have confined scope as they address particular spin technologies. This paper attempts to provide a comprehensive review on the subject and fill the information void regarding the state of the art aircraft spin technologies.

scholarly journals Vulnerable adults in police custody

2019 ◽  
Vol 22 (1) ◽  
pp. 5-8
Author(s):  
Ian Cummins
Keyword(s):  
Design Methodology ◽  
Research Literature ◽  
Police Custody ◽  
England And Wales ◽  
Content Type ◽  
Increased Risk ◽  
Vulnerable Adults

Purpose The purpose of this paper is to discuss the recent National Appropriate Adult Network (NAAN) report on the role of the appropriate adult. Design/methodology/approach This paper is based on the NAAN report and a review of relevant policy and research literature. Findings There to Help 2 highlights that there are still significant gaps in the provision of appropriate adult schemes across England and Wales. These gaps potentially place vulnerable adults at increased risk. Originality/value This paper is a review of recent research.

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