Numerical and experimental analysis of rotating wheel in contact with the ground

2018 ◽  
Vol 28 (5) ◽  
pp. 1203-1217 ◽  
Author(s):  
Michal Kulak ◽  
Maciej Karczewski ◽  
Pawel Lesniewicz ◽  
Krzysztof Olasek ◽  
Bas Hoogterp ◽  
...  
Keyword(s):  
Aerodynamic Drag ◽  
Cfd Simulations ◽  
Content Type ◽  
Car Body ◽  
Aerodynamic Properties ◽  
University Of Technology ◽  
Ansys Cfx ◽  
Key Factor ◽  
Computational Fluid Dynamics Cfd ◽  
Practical Implications

Purpose This paper aims to provide the results of investigations concerning an influence of the tyre with longitudinal grooves on the car body aerodynamics. It is considered as an important aspect affecting the vehicle aerodynamic drag. Design/methodology/approach To investigate a contribution of grooved tyres to the overall vehicle drag, three wind tunnel experimental campaigns were performed (two by Peugeot Société Anonyme Peugeot Citroen, one at the Lodz University of Technology). In parallel, computational fluid dynamics (CFD) simulations were conducted with the ANSYS CFX software to enable formulation of wider conclusions. Findings The research shows that optimised tread patterns can be derived on a single tyre via a CFD study in combination with a controlled experiment to deliver designs actively lowering the overall vehicle aerodynamic drag. Practical implications A reduction in the aerodynamic drag is one of ways to decrease vehicle fuel consumption. Alternatively, it can be translated into an increase in the maximum travel velocity and the maximum distance driven (key factor in electric vehicles), as well as in a reduction of CO2 emissions. Finally, it can improve the vehicle driving and steering stability. Originality/value The tyre tread pattern analysis on isolated wheels provides an opportunity to cut costs of R&D and could be a step towards isolating aerodynamic properties of tyres, irrespective of the car body on which they are applied.

Assessment of modelling strategies for film cooling

2017 ◽  
Vol 27 (5) ◽  
pp. 1118-1127 ◽  
Author(s):  
Lorenzo Mazzei ◽  
Antonio Andreini ◽  
Bruno Facchini
Keyword(s):  
Film Cooling ◽  
Computational Cost ◽  
Flat Plates ◽  
Cfd Simulations ◽  
Significant Saving ◽  
Content Type ◽  
Modelling Strategies ◽  
Computational Fluid Dynamics Cfd ◽  
Innovative Techniques ◽  
Practical Implications

Purpose Effusion cooling represents one the most innovative techniques for the thermal management of aero-engine combustors liners. The huge amount of micro-perforations implies a significant computational cost if cooling holes are included in computational fluid dynamics (CFD) simulations; therefore, many efforts are reported in literature to develop lower-order approaches aiming at limiting the number of mesh elements. This paper aims to report a numerical investigation for validating two approaches for modelling film cooling, distinguished according to the way coolant is injected (i.e. through either point or distributed mass sources). Design/methodology/approach The approaches are validated against experimental data in terms of adiabatic effectiveness and heat transfer coefficient distributions obtained for effusion cooled flat plates. Additional reynolds-averaged naver stokes (RANS) simulations were performed meshing also the perforation, so as to distinguish the contribution of injection modelling with respect to intrinsic limitations of turbulence model modelling. Findings Despite the simplified strategies for coolant injection, this work clearly shows the feasibility of obtaining a sufficiently accurate reproduction of coolant protection in conjunction with a significant saving in terms of computational cost. Practical/implications The proposed methodologies allow to take into account the presence of film cooling in simulations of devices characterized by a huge number of holes. Originality/value This activity represents the first thorough and quantitative comparison between two approaches for film cooling modelling, highlighting the advantages involved in their application.

Gender differences in Taiwan’s hypermarkets

2016 ◽  
Vol 28 (4) ◽  
pp. 650-662 ◽  
Author(s):  
Tsung-Sheng Chang ◽  
Hsiaoping Yeh
Keyword(s):  
Gender Differences ◽  
Customer Behavior ◽  
Marketing Strategies ◽  
Male And Female ◽  
Content Type ◽  
Product Categories ◽  
Traditional Markets ◽  
Key Factor ◽  
Practical Implications

Purpose Hypermarkets face a very competitive environment, as their rivals also include traditional markets, convenient stores and supermarkets. In addition to offering innovative services, hypermarket managers must also pay attention to customer shopping patterns and behaviors in order to gain market share. The purpose of this paper is to posit that there will be significant differences between male and female hypermarket customers in terms of both shopping time and categories of goods purchased. Design/methodology/approach To investigate actual shopping behaviors, this study observed customers in hypermarkets and recorded how long they spent shopping and what they purchased. Findings The results of this study implied that gender is a key factor that affects both shopping time and the goods purchased in Taiwanese hypermarkets. The empirical findings also indicated that customers favor certain goods categories. Practical implications The results of this study provide details of the differences between male and female hypermarket customers, with which managers can use to develop better marketing strategies. Originality/value The purpose of this study is to show hypermarket retailers how gender differences affect customer behavior in this context. It also presents a consumer product categories list for hypermarkets, and this can be used as a reference for follow-up studies.

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.

CFD simulation of empty fuel tanks separation from a trainer jet

2020 ◽  
Vol 92 (10) ◽  
pp. 1459-1468
Author(s):  
Aleksander Olejnik ◽  
Adam Dziubiński ◽  
Łukasz Kiszkowiak
Keyword(s):  
Cfd Simulation ◽  
Body Movement ◽  
Cfd Simulations ◽  
Content Type ◽  
Sequential Release ◽  
Wind Tunnel Data ◽  
Computational Fluid Dynamics Cfd ◽  
External Forces ◽  
Additional Value ◽  
Control Surfaces

Purpose This study aims to create 6-degree of freedom (SDOF) for computational fluid dynamics (CFD) simulations of body movement, and to validate using the experimental data for empty tank separation from I-22 Iryda jet trainer. The procedure has an ability to be modified or extended, to simulate, for example, a sequential release from the joints. Design/methodology/approach A set of CFD simulations are calculated. Both the SDOF procedure and the CFD simulation settings are validated using the wind tunnel data available for the aircraft. Findings The simulation using designed procedure gives predictable results, but offers availability to be modified to represent external forces, i.e. from body interaction or control system without necessity to model the control surfaces. Practical implications The procedure could be used to model the separation of external stores and design the deployment of anti-radar chaff, flares or ejection seats. Originality/value The work presents original work, caused by insufficient abilities of original SDOF procedure in ANSYS code. Additional value is the ability of the procedure to be easily modified.

The simulation of single wraparound fin on a semi-cylindrical missile body

2020 ◽  
Vol 92 (3) ◽  
pp. 418-427 ◽  
Author(s):  
Nayhel Sharma ◽  
Rakesh Kumar
Keyword(s):  
Research Study ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Future Research ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Predicted Values ◽  
Characteristic Trend ◽  
Practical Implications

Purpose The purpose of this paper is to establish a freestream computational fluid dynamics (CFD) model of a three-dimensional non-spinning semi-cylindrical missile model with a single wrap around fin in Mach 2.70-3.00M range and 0° angle of attack, and ultimately establishing itself for future research study. Design/methodology/approach In this study, the behaviour of flow around the fin was investigated using a κ-ϵ turbulence model of second-order of discretization. This was done using a highly structured mesh. Additionally, an inviscid CFD simulation involving the same boundary conditions have also been carried out for comparison. Findings The obtained values of aerodynamic coefficients and pressure contours visualizations are compared against their experimental and computational counterparts. A typical missile aerodynamic characteristic trend can be seen in the current CFD. Practical implications The predicted values of the aerodynamic coefficients of this single fin model have also been compared to those of the full missile body comprising of four fins from the previous research studies, and a similar aerodynamic trend can be seen. Originality/value This study explores the possibility of the use of turbulence modelling in a single fin model of a missile and provides a basic computational model for further understanding the flow behaviour near the fin.

Investigation of the flight behavior of a flare-stabilized projectile using 6DoF simulations coupled with CFD

2019 ◽  
Vol 30 (9) ◽  
pp. 4185-4201
Author(s):  
Daniel Klatt ◽  
Michael Proff ◽  
Robert Hruschka
Keyword(s):  
Degrees Of Freedom ◽  
Rigid Body Dynamics ◽  
Flight Behavior ◽  
Free Flight ◽  
Aerodynamic Coefficients ◽  
Cfd Simulations ◽  
Time Resolved ◽  
Content Type ◽  
Six Degrees Of Freedom ◽  
Computational Fluid Dynamics Cfd

Purpose The present work aims to investigate the capabilities of accurately predicting the six-degrees-of-freedom (6DoF) trajectory and the flight behavior of a flare-stabilized projectile using computational fluid dynamics (CFD) and rigid body dynamics (RBD) methods. Design/methodology/approach Two different approaches are compared for calculating the trajectory. First, the complete matrix of static and dynamic aerodynamic coefficients for the projectile is determined using static and dynamic CFD methods. This discrete database and the data extracted from free-flight experiments are used to simulate flight trajectories with an in-house developed 6DoF solver. Second, the trajectories are simulated solving the 6DoF motion equations directly coupled with time resolved CFD methods. Findings Virtual fly-out simulations using RBD/CFD coupled simulation methods well reproduce the motion behavior shown by the experimental free-flight data. However, using the discrete database of aerodynamic coefficients derived from CFD simulations shows a slightly different flight behavior. Originality/value A discrepancy between CFD 6DoF/RBD simulations and results obtained by the MATLAB 6DoF-solver based on discrete CFD data matrices is shown. It is assumed that not all dynamic effects on the aerodynamics of the projectile are captured by the determination of the force and moment coefficients with CFD simulations based on the classical aerodynamic coefficient decomposition.

RBF-based mesh morphing approach to perform icing simulations in the aviation sector

2019 ◽  
Vol 91 (4) ◽  
pp. 620-633 ◽  
Author(s):  
Corrado Groth ◽  
Emiliano Costa ◽  
Marco Evangelos Biancolini
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Ansys Fluent ◽  
Content Type ◽  
Mesh Morphing ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses ◽  
2D And 3D ◽  
First Time ◽  
Practical Implications

Purpose Numerical simulation of icing has become a standard. Once the iced shape is known, however, the analyst needs to update the computational fluid dynamics (CFD) grid. This paper aims to propose a method to update the numerical mesh with ice profiles. Design/methodology/approach The present paper concerns a novel and fast radial basis functions (RBF) mesh morphing technique to efficiently and accurately perform ice accretion simulations on industrial models in the aviation sector. This method can be linked to CFD analyses to dynamically reproduce the ice growth. Findings To verify the consistency of the proposed approach, one of the most challenging ice profile selected in the LEWICE manual was replicated and simulated through CFD. To showcase the effectiveness of this technique, predefined ice profiles were automatically applied on two-dimensional (2D) and three-dimensional (3D) cases using both commercial and open-source CFD solvers. Practical implications If ice accreted shapes are available, the meshless characteristic of the proposed approach enables its coupling with the CFD solvers currently supported by the RBF4AERO platform including OpenFOAM, SU2 and ANSYS Fluent. The advantages provided by the use of RBF are the high performance and reliability, due to the fast application of mesh smoothing and the accuracy in controlling surface mesh nodes. Originality/value As far as authors’ knowledge is concerned, this is the first time in scientific literature that RBF are proposed to handle icing simulations. Due to the meshless characteristic of the RBF mesh morphing, the proposed approach is cross solver and can be used for both 2D and 3D geometries.

scholarly journals Investigation of Influence of Adjustments in Cyclist Arm Position on Aerodynamic Drag Using Computational Fluid Dynamics

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 159
Author(s):  
Knut Erik Teigen Giljarhus ◽  
Daniel Årrestad Stave ◽  
Luca Oggiano
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Aerodynamic Drag ◽  
Time Trial ◽  
Elbow Extension ◽  
Cfd Simulations ◽  
Arm Position ◽  
Sport Activities ◽  
The Face ◽  
Computational Fluid Dynamics Cfd

In professional cycling, even small adjustments in position could mean that valuable seconds are gained over the course of a time-trial race. This study investigates the influence of arm position on the aerodynamic drag of a cyclist. Based on a 3D scanned model of a professional cyclist, 64 alternate positions are generated. The parameters that are investigated are the distance between elbows, elbow extension, and distance between hands. Computational fluid dynamics (CFD) simulations of all positions are performed, and a regression model is built from the results. The results indicate that the optimal posture is achieved for a minimum in all investigated parameters, which means that the hands and elbows should be kept together with hands up towards the face. Furthermore, elbow extension seems to be the most crucial parameter, followed by the distance between elbows, and then by the distance between the hands. The presented methodology can be applied to study other parameters relevant to cycling aerodynamics or be applied to other sport activities as well.

scholarly journals Altruism born of suffering among emerging adults in Northern Ireland

2018 ◽  
Vol 10 (3) ◽  
pp. 157-169 ◽  
Author(s):  
Laura K. Taylor ◽  
Jeffrey R. Hanna
Keyword(s):  
Northern Ireland ◽  
Emerging Adults ◽  
Content Type ◽  
Mediation Analyses ◽  
Key Factor ◽  
Group Identities ◽  
The Impact ◽  
Perceived Harm ◽  
Practical Implications

Purpose The purpose of this paper is to explore altruism born of suffering (ABS), a theory that explains how the experience of suffering within one’s own life may result in the motivation to help others, even outgroup members. Design/methodology/approach Participants were 186 emerging adults (63 per cent female, 37 per cent male; 69 per cent Protestant, 41 per cent Catholic; average age =21.3, SD=2.57 years old) in Northern Ireland, a setting of protracted intergroup conflict. Participants were randomly assigned to an in/outgroup condition, read four types of adversity that occurred to same-sex victim(s), and indicated their empathetic response and how much they would like to help the victims. Findings Moderated mediation analyses revealed that empathy for the victim partially mediated the impact of perceived harm on desire to help; moreover, recent negative life events strengthened the link between harm and empathy. The path between empathy and helping was stronger in the outgroup compared to the ingroup condition. Practical implications These findings support ABS, highlighting empathy as a key factor underlying more constructive intergroup relations in a divided society. Originality/value This paper extends previous research on ABS by focusing on a post-accord context. The value of the current analyses demonstrate the important role of fostering empathy to promote outgroup helping in settings of divisive group identities.

Researchers as enablers of commercialization at an entrepreneurial university

2017 ◽  
Vol 36 (2) ◽  
pp. 217-232 ◽  
Author(s):  
Eva Berggren
Keyword(s):  
Academic Research ◽  
Entrepreneurial University ◽  
Content Type ◽  
Individual Motivation ◽  
Commercial Use ◽  
University Of Technology ◽  
Academic Researchers ◽  
Established Firms ◽  
Practical Implications

Purpose The purpose of this paper is to explore and visualize alternative ways – how and by whom – that academic research can come into commercial use. Design/methodology/approach This study in the Swedish context investigates one entrepreneurial university, Chalmers University of Technology. In total, 18 interviews were conducted about researchers’ views on commercialization and on how research comes into commercial use. Findings Five propositions are advocated in relation to researchers’ role as enablers of others’ commercialization. The concept of “need for utilization” is introduced as the critical explanation for researchers’ readiness to transfer knowledge mainly via alumni to established companies. Practical implications This study suggests that both universities and policy should acknowledge alternative ways of commercialization of academic research instead of putting all efforts on trying to transform unwilling academic researchers into entrepreneurs. One alternative is to foster ongoing contacts between researchers and alumni, who make commercial use of academic research in established firms. Originality/value This study furthers the knowledge about researchers’ individual motivation for commercialization, as driven by a “need for utilization.” By showing how researchers enable others commercialization, this study broadens the prevailing focus on researchers’ formation of university spin-offs as the essential output from entrepreneurial universities. The results also contribute to understanding the role of alumni in knowledge transfer to existing industry.

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