Ezhilmaran G., Sekar S., Sathish Kumar K. and Thanigaiarasu S.
This study aims to investigate the effect of slanted perforation diameter in tabs for the control of Mach 1.4 underexpanded supersonic jet flow characteristics.
Abstract
Purpose
This study aims to investigate the effect of slanted perforation diameter in tabs for the control of Mach 1.4 underexpanded supersonic jet flow characteristics.
Design/methodology/approach
Numerical investigation was carried out for NPR 5 to analyze the effect of slanted perforation diameter in tabs to control the Mach 1.4 jet. Four sets of tabs with slanted circular perforation geometries (Φp = 1, 1.5, 2 and 2.5 mm) were considered in this study. The inclination angle of 20° (αP) with reference to the jet axis was maintained constant for all the four tabs considered.
Findings
Determined value indicates there is a 68%, 71%, 73% and 75% drop in supersonic core for the Φp = 1, 1.5, 2.0 and 2.5 mm, respectively. The results show that the tabs with 2.5 mm perforation diameter were found to be efficient in reducing the supersonic jet core in comparison with other tab cases. The reduction in supersonic core length is due to the extent of miniscule vortices exuviating from slanted small and large diameter perforation in the tabs.
Practical implications
The concept of slanted perforation can be applied in scramjet combustion, which finds its best application in hypersonic vehicles and in noise suppression in fighter aircraft.
Originality/value
Slanted perforation and circular shapes with different diameters have not been studied in the supersonic regime. Examining the effect of circular diameter in slanted perforation is an innovation in this research paper.
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Arun Kumar P. and Lavanya Vilvanathan
This study aims to understand the impact of negative supervisor gossip on job performance among South Indian hotel employees. The focus is not just on the direct influence, but…
Abstract
Purpose
This study aims to understand the impact of negative supervisor gossip on job performance among South Indian hotel employees. The focus is not just on the direct influence, but also on the mediating role of feedback-seeking behaviour (FSB) and the moderating effects of the agreeableness trait.
Design/methodology/approach
Through purposive sampling, data was garnered from South Indian hotel employees. Comprehensive analyses were performed using partial least squares structural equation modelling.
Findings
The analysis shows that FSB plays a mediating role in the positive relationship between negative supervisor gossip and job performance. In addition, the influence of gossip on FSB and subsequent job performance was more pronounced for employees with high agreeableness.
Research limitations/implications
This research underscores the complex interplay between negative supervisor gossip and job performance, revealing that such gossip can catalyze FSB process in employees. It suggests that under certain conditions, negative gossip can be transformed into a constructive force that enhances job performance, challenging traditional perceptions of gossip in the workplace.
Practical implications
The findings underscore the importance of understanding the effects of workplace dynamics, like supervisor gossip, on employee behaviour and performance. Recognizing the influence of individual personality traits, such as agreeableness, can guide management strategies for fostering a productive work environment.
Originality/value
This research sheds light on the intricate interplay between negative supervisor gossip, FSB and agreeableness, offering a novel perspective on their combined impact on job performance. It not only enriches the existing literature on workplace communication but also broadens the understanding of the role of personality traits in shaping employee responses and outcomes.
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P. Arun Kumar, S. Nivethitha and Lavanya Vilvanathan
Green HRM practices in the hospitality sector are now receiving growing interest. However, the extent to which these practices contribute towards employee non-green workplace…
Abstract
Purpose
Green HRM practices in the hospitality sector are now receiving growing interest. However, the extent to which these practices contribute towards employee non-green workplace outcomes remains largely unknown. This study explores the relationships among green HRM practices, happiness at work, employee resilience, and feedback-seeking behaviour.
Design/methodology/approach
The study employs two-wave data from a sample of 306 five-star hotel employees in India. Using partial least square-structural equation modelling, the relationships are tested.
Findings
The study’s results demonstrate that green HRM practices positively impact happiness at work, employee resilience, and feedback-seeking behaviour. Additionally, the relationship between green HRM practices and feedback-seeking behaviour and employee resilience is mediated by happiness at work.
Research limitations/implications
Drawing on the Job Demands-Resources Theory, Social Exchange Theory, and Broaden and Build theory, this paper proposes that green HRM practices can contribute to happiness at work, employee resilience, and feedback-seeking behaviour.
Practical implications
To establish a positive connection between green HRM practices and employee outcomes, organizations must recognize the vital role played by happiness at work as a mediator. This means that organizations must implement green HRM practices and ensure their positive impact on employee happiness at work.
Originality/value
The originality of this research lies in its holistic approach to green HRM outcomes, suggesting that the benefits of these practices extend beyond environmental impacts to influence the psychological and behavioural dimensions of employees.
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Sathish Kumar K. and Senthilkumar Chidambaram
The purpose of this study is to increase the jet mixing effectiveness of Mach 1.6 axisymmetric jet using semi-circular corrugated triangular tabs (Tabs A, B and C), in which the…
Abstract
Purpose
The purpose of this study is to increase the jet mixing effectiveness of Mach 1.6 axisymmetric jet using semi-circular corrugated triangular tabs (Tabs A, B and C), in which the locations of the semi-circular corrugations are varied along the leaned sides of the triangular tabs.
Design/methodology/approach
The tabs are fixed at the exit of the nozzle facing each other 180° apart. To quantify the jet mixing effectiveness of the semi-circular corrugated tabs, Pitot pressure measurements were carried out for the cases of over-expansion, marginally over-expansion and under-expansion levels of Mach 1.6 jet, along the jet centerline and the jet spread, along and normal to the tab axis.
Findings
The results exhibit that the semi-circular corrugated Tab A augments the jet mixing when compared to Tabs B and C. This impact in jet mixing is strongly due to the small-scale vortices shed from the tabs and the mixed effect of the corrugation locations and expansion ratio. The maximum percentage reduction in core length is about 73.6 per cent for the jet with semi-circular corrugated Tab A at NPR 5, whereas it is 71.4 and 67.1 per cent for Tabs B and C, respectively.
Practical implications
The reduction in core length of the jet with minimum thrust loss is obtained by controlling the jet used with semi-circular corrugated triangular tabs of equal blockage ratio 5.12 per cent with respect to the nozzle exit diameter.
Originality/value
The locations of the semi-circular corrugations varied systematically at the equally leaned sides of the triangular tab ensure the novelty of this study.
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Arun Prasad Ramasamy, Krishna Narendran, Ilakkiya Selvaraj, Harhini S and Subramanian Thanigaiarasu
This paper aims to present the mixing and decay characteristics of Mach 0.8 elliptic jet manipulated by air tabs, through numerical simulation.
Abstract
Purpose
This paper aims to present the mixing and decay characteristics of Mach 0.8 elliptic jet manipulated by air tabs, through numerical simulation.
Design/methodology/approach
The Air Tabs are secondary jets injected through two 1-mm diameter tubes, which are placed at the exit plane of the elliptic primary nozzle. Two air tab configurations are considered for the present study; in the first case, they are placed along the major axis, and in the second case along the minor axis of the elliptic nozzle exit. The air tab Mach numbers considered are 0.8, 0.9 and 1.0. The numerical simulations have been performed in ANSYS-CFX software using the k-e turbulence model.
Findings
The jet centerline (X) total pressure decay reveals that air tabs placed along the minor axis promote jet mixing more efficiently than those placed along the major axis. It is also observed that the air tabs along the minor axis provoke the jet to split into two parts thus resulting in faster spread in the perpendicular direction (Z). When compared against the uncontrolled jet, air tabs at Mach 1.0 placed along the minor axis produce 80% reduction in the potential core, whereas that along the major axis brings down the axis-switching location to 0.95 Deq from 3.7 Deq.
Practical implications
In aerospace applications, enhancing the mixing between fuel and air would result in better combustion efficiency, faster exhaust jet mixing with ambient, which in turn result in reduced jet acoustics as well as infrared signature, thereby promotes environmental sustainability.
Originality/value
To the best of the authors’ knowledge, there has not been a thorough analysis of the effects of air tabs on the mixing and decay characteristics of elliptic Mach 0.8 jet.
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This study investigates how performance pressure affects feedback-seeking and innovative work behaviors. The study also examines the effect of extraversion on the performance…
Abstract
Purpose
This study investigates how performance pressure affects feedback-seeking and innovative work behaviors. The study also examines the effect of extraversion on the performance pressure–FSB relationship.
Design/methodology/approach
The hypotheses in this study were tested by analyzing two-wave data collected from a sample of employees in the information technology sector in India using the PLS-SEM approach.
Findings
Our findings revealed that individuals possessing extraverted personality traits exhibited a positive response to performance pressure, thereby enhancing their FSB. Moreover, our results demonstrated that FSB mediates the relationship between performance pressure and IWB.
Research limitations/implications
The results underscore the importance of individual variations in personality traits, particularly extraversion, in influencing how employees respond to performance pressure. By providing insights into the mediating mechanism of feedback-seeking behavior, our study contributes to a deeper understanding of the interplay between performance pressure, feedback-seeking behavior and innovative work behavior.
Practical implications
Managers should consider extraversion as a factor in the relationship between performance pressure and FSB, adapting strategies and support systems accordingly. Creating a feedback-oriented culture and providing resources for extroverts during high-pressure periods can enhance their coping mechanisms.
Originality/value
Previous research has provided a limited exploration of the mechanisms that establish the connection between job demands and innovative work behaviors. This study contributes by uncovering the previously unexplored relationship between performance pressure, extraversion, feedback-seeking behavior and, subsequently, innovative work behavior.
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Vadiraj Rao, N. Suresh and G.P. Arun Kumar
The majority of previous studies made on Recycled Concrete Aggregates (RCA) are limited to the utilisation of non-structural grade concrete due to unfavourable physical…
Abstract
Purpose
The majority of previous studies made on Recycled Concrete Aggregates (RCA) are limited to the utilisation of non-structural grade concrete due to unfavourable physical characteristics of RCA including the higher absorption of water, tending to increased water requirement of concrete. This seriously limits its applicability and as a result it reduces the usage of RCA in structural members. In the present study, the impact of hybrid fibres on cracking behaviour of RCA concrete beams along with the inclusion of reinforcing steel bars under two-point loading system exposed to different sustained elevated temperatures are being investigated.
Design/methodology/approach
RCA is substituted for Natural Coarse Aggregates (NCA) at 0, 50 and 100 percentages. The study involves testing of 150 mm cubes and beams of size (700 × 150 × 150) mm, i.e. with steel reinforcing bars along with the addition of 0.35% Steel fibres+ 0.15% polypropylene fibres. The specimens are being exposed to temperatures from 100° to 500°C with 100° interval for 2 h. Studies were made on the post crack analysis, which includes the measurement of crack width, crack length and load at first crack. The crack patterns were analysed in order to understand the effect of fibres and RCA at sustained elevated temperatures.
Findings
The result shows that ultimate load carrying capacity of reinforced concrete beams and load at first crack decreases with the raise in temperatures and increased percentage of RCA content in the mix. Further that 100% RCA replacement specimens showed lesser cracks when compared to the other mixes and the inclusion of fibres enhances the flexural capacity of members highlighting the importance of fibres.
Practical implications
RCA can be used for structural purposes and the study can be projected for assessing the performance of real structures with the extent of fire damage when recycled aggregates are used.
Social implications
Most of recycled materials can be used in the regular concrete which solves two problems namely avoiding the dumping of C&D waste and preventing the usage of natural aggregates. Hence the study provides sustainable option for the production of concrete.
Originality/value
The reduction in capacity of flexural members due to the utilisation of recycled aggregates can be negated by the usage of fibres. Hence improved flexural performance is observed for specimens with fibres at sustained elevated temperatures.
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Jaimon Dennis Quadros, S.A. Khan and Hanumantharaya R.
The purpose of this study is to evaluate the effect of tabs having different corner geometries on the flow characteristics of a supersonic convergent–divergent (C-D) nozzle.
Abstract
Purpose
The purpose of this study is to evaluate the effect of tabs having different corner geometries on the flow characteristics of a supersonic convergent–divergent (C-D) nozzle.
Design/methodology/approach
A circular C-D nozzle of Mach 2.0 was used, and the tabs were positioned at the exit of the nozzle in diametrically opposite directions. Three tabs having different corner geometry implemented in the experiments were rectangular tab with triangular top edge, triangular tab with a bell-shaped edge and tapered tab. The pressure profiles across the tabs and the centerline pressure decay along the jets were measured. The shadowgraph technique illustrated the waves present in the center of an oncoming jet. The nozzle pressure ratios (NPR) were varied from 4 to 8, in the steps of one, covering various overexpansion and under expansion levels at the exit of the nozzle.
Findings
The results showed tapered tabs act as a better mixing promoter than the other tabs used in the study. A reduction of 91.25% in core length for NPR 8 was observed for the tapered tabs. Subsequently, core length reductions generated by triangular tabs with a bell-shaped top edge were 87.5%, and those caused by rectangular tabs with a triangular top edge were 7.5%.
Practical implications
The research results could be used for designing combustion chambers and chemical reactors that require jets to enhance mixing levels.
Originality/value
The tabs having three different corners geometries, i.e. sharp or pointed, bell-shaped and straight edge has never been investigated before. The idea of only modifying corners is the innovative step of this research.
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Sathish Kumar K., Senthilkumar Chidambaram and Naren Shankar Radha Krishnan
This paper aims to present the jet mixing effectiveness of triangular tabs with semi-circular corrugations to control the subsonic and sonic correctly expanded jets.
Abstract
Purpose
This paper aims to present the jet mixing effectiveness of triangular tabs with semi-circular corrugations to control the subsonic and sonic correctly expanded jets.
Design/methodology/approach
Three semi-circular corrugated triangular tabs (Tab A, Tab B and Tab C) of equal blockage 5.11% are used, in which the corrugation locations on the tabs are varied. The offset distance between the semi-circular corrugations at the leaned edges of the triangular tabs are 0.0, 0.75 and 1.5 mm for the Tabs A, B and C, respectively. Two identical semi-circular corrugated tabs has been placed exactly 180° apart at the exit of the convergent nozzle. The pitot pressure measurements were taken to study the jet mixing characteristics of the tabs for the jet exit Mach numbers of 0.6, 0.8 and 1.0, and it is compared with the free jet.
Findings
The jet centerline pitot pressure decay reveals that, Tab A is very effective than Tab B and Tab C. For the jet exit Mach numbers of 0.6, 0.8 and 1.0, the potential core reduction for the Tab A is found to be 69.1%, 69.7% and 70.8%, respectively, when compared with the free jet.
Practical implications
The semi-circular corrugated triangular tabs were found to be more effective than the plain triangular tabs of equal blockage ratio for reducing the core length with minimum thrust loss.
Originality/value
The offset distance of the semi-circular corrugations are varied along the leaned sides of the triangular tabs, which is the novelty of this study.
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Decision-makers often struggle to combine advice with their own intuition. This study examines how advice-giver traits and decision-makers’ intuition influence advice uptake. We…
Abstract
Purpose
Decision-makers often struggle to combine advice with their own intuition. This study examines how advice-giver traits and decision-makers’ intuition influence advice uptake. We present a novel typology based on decision-makers’ trust in advice-givers and their perceived expertise.
Design/methodology/approach
This qualitative study uses a sample of publicly available interview data with 51 elite performers. Using inductive and content analysis, we explore the mediation between decision-makers’ intuitive competence (ability to effectively deploy intuition in interface with advice) and their autonomy (self-endorsement from past performance).
Findings
We identify four sources of advice: mentor advice, specialist advice, confidant advice and commentator advice. Drawing on instances of different sources of advice along varying degrees of trust and expertise, we propose a framework for interaction between intuitional competence and advice characteristics.
Originality/value
We offer a novel way of contextualising nuanced forms of advice and provide a structured typology of sources, characterised by trust and expertise. This typology and our findings help reconcile contradictions in decision-making research. Finally, we offer practical guidance for the uptake of advice.