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Full-Text Articles in Engineering
Reducing Transonic Wind Tunnel Sting Interference Effects For Concealed Store Release Testing, Graham Doig, Goran Bogdan, Kaveh R. Kabir, Murray R. Snyder
Reducing Transonic Wind Tunnel Sting Interference Effects For Concealed Store Release Testing, Graham Doig, Goran Bogdan, Kaveh R. Kabir, Murray R. Snyder
Aerospace Engineering
Internal weapons bays are becoming increasingly common on aircraft for reasons of stealth and aerodynamic performance, and will be even more prevalent on coming generations of unmanned combat aerial vehicles (UCAVs). Wind tunnel testing of store releases to assess forces and moments for safety and clearance must be conducted with a store mounted to an angled strut rather than a conventional rear sting, to allow the full range of motion as the store “drops” from inside the aircraft. Interference from this strut can disrupt the flowfields and thus the reliability of moments obtained, and therefore an investigation was conducted to …
The Effects Of Simplifications On Isolated Wheel Aerodynamics, Sammy Diasinos, Tracie Barber, Graham Doig
The Effects Of Simplifications On Isolated Wheel Aerodynamics, Sammy Diasinos, Tracie Barber, Graham Doig
Aerospace Engineering
In order to study the aerodynamic forces and flow features of rotating wheels, compromises and simplifications are often made in wind tunnel testing, and more frequently so in numerical modelling. A CFD approach similar to that commonly used in industry was utilised to investigate common assumptions involving; the influence of geometric fidelity in wheel hub regions, ground representation, the modelling of the contact patch, and the effects of rotation on separation. It was found that the separation and wake characteristics were strongly influenced by the rotation of the wheel; the separation point changed by as much as 90% compared to …
Design Of High-Area-Ratio Nozzle Contours Using Circular Arcs, K. Schomberg, J. Olsen, Graham Doig
Design Of High-Area-Ratio Nozzle Contours Using Circular Arcs, K. Schomberg, J. Olsen, Graham Doig
Aerospace Engineering
A method using circular arcs to generate the divergence contour in a supersonic nozzle is presented. Comparison of the arc-based geometry with existing nozzle contours demonstrated that an average decrease in axial length of 7.5% can be expected when the arc-based design method is applied to a core stage nozzle. Two arc-based and conventional nozzles were evaluated numerically across the pressure operating range of a core stage engine to compare calculated thrust and separation characteristics with existing data. The length-weighted thrust coefficient was increased by 0.3–1.8% in the arc-based design in both configurations. Separated flow characteristics were compared using contours …
Computational Aerodynamic Analysis Of A Micro-Ct Based Bio-Realistic Fruit Fly Wing, Joshua Brandt, Graham Doig, Naomi Tsafnat
Computational Aerodynamic Analysis Of A Micro-Ct Based Bio-Realistic Fruit Fly Wing, Joshua Brandt, Graham Doig, Naomi Tsafnat
Aerospace Engineering
The aerodynamic features of a bio-realistic 3D fruit fly wing in steady state (snapshot) flight conditions were analyzed numerically. The wing geometry was created from high resolution micro-computed tomography (micro-CT) of the fruit fly Drosophila virilis. Computational fluid dynamics (CFD) analyses of the wing were conducted at ultra-low Reynolds numbers ranging from 71 to 200, and at angles of attack ranging from -10° to +30°. It was found that in the 3D bio-realistc model, the corrugations of the wing created localized circulation regions in the flow field, most notably at higher angles of attack near the wing tip. Analyses …
Analysis Of A Low-Angle Annular Expander Nozzle, Kyll Schomberg, John Olsen, Graham Doig
Analysis Of A Low-Angle Annular Expander Nozzle, Kyll Schomberg, John Olsen, Graham Doig
Aerospace Engineering
An experimental and numerical analysis of a low-angle annular expander nozzle is presented to observe the variance in shock structure within the flow field. A RANS-based axisymmetric numerical model was used to evaluate flow characteristics and the model validated using experimental pressure readings and schlieren images. Results were compared with an equivalent converging-diverging nozzle to determine the capability of the wake region in varying the effective area of a low-angle design. Comparison of schlieren images confirmed that shock closure occurred in the expander nozzle, prohibiting the wake region from affecting the area ratio. The findings show that a low angle …
Techniques For Aerodynamic Analysis Of Cornering Vehicles, James Keogh, Tracie J. Barber, Sammy Diasinos, Graham Doig
Techniques For Aerodynamic Analysis Of Cornering Vehicles, James Keogh, Tracie J. Barber, Sammy Diasinos, Graham Doig
Aerospace Engineering
When a vehicle travels through a corner it can experience a significant change in aerodynamic performance due to the curved path of its motion. The yaw angle of the flow will vary along its length and the relative velocity of the flow will increase with distance from the central axis of its rotation. Aerodynamic analysis of vehicles in the cornering condition is an important design parameter, particularly in motorsport. Most racing-cars are designed to produce downforce that will compromise straight-line speed to allow large gains to be made in the corners. Despite the cornering condition being important, aerodynamicists are restricted …
20 Years Of Unsw Australia's Sunswift Solar Car Team: A New Moment In The Sun, But Where To Next?, Hayden Charles Smith, Sam Paterson, Clara Mazzone, Sammy Diasinos, Graham Doig
20 Years Of Unsw Australia's Sunswift Solar Car Team: A New Moment In The Sun, But Where To Next?, Hayden Charles Smith, Sam Paterson, Clara Mazzone, Sammy Diasinos, Graham Doig
Aerospace Engineering
The Sunswift Solar Car project has been running at UNSW Australia in Sydney for 20 years as of 2015. It is an entirely student-run endeavour which revolves around the design and development of a solar/electric vehicle nominally designed to compete in the World Solar Challenge rally from Darwin to Adelaide every 2 years. The student cohort is drawn from a range of schools, disciplines and backgrounds, and the team has been increasingly successful and high-profile particularly in its second decade. The excellent level of hands-on training that the project provides to students is not rewarded with academic credit yet many …
Explosive-Driven Shock Wave And Vortex Ring Interaction With A Propane Flame, P. Giannuzzi, M. J. Hargather, Graham Doig
Explosive-Driven Shock Wave And Vortex Ring Interaction With A Propane Flame, P. Giannuzzi, M. J. Hargather, Graham Doig
Aerospace Engineering
Experiments were performed to analyze the interaction of an explosively driven shock wave and a propane flame. A 30 g explosive charge was detonated at one end of a 3-m-long, 0.6-m-diameter shock tube to produce a shock wave which propagated into the atmosphere. A propane flame source was positioned at various locations outside of the shock tube to investigate the effect of different strength shock waves. High-speed retroreflective shadowgraph imaging visualized the shock wave motion and flame response, while a synchronized color camera imaged the flame directly. The explosively driven shock tube was shown to produce a repeatable shock wave …
The Influence Of Cornering On The Vortical Wake Structures Of An Inverted Wing, James Keogh, Graham Doig, Sammy Diasinos, Tracie Barber
The Influence Of Cornering On The Vortical Wake Structures Of An Inverted Wing, James Keogh, Graham Doig, Sammy Diasinos, Tracie Barber
Aerospace Engineering
The aerodynamic performance of inverted wings on racing-car configurations is most critical when cornering; however, current wind tunnel techniques are generally limited to the straight-line condition. The true cornering condition introduces complexity because of the curvature of the freestream flow. This results in an increase in the tangential velocity with increasing distance from the instantaneous centre of rotation and causes the front wing to be placed at a yaw angle. Numerical simulations were used to consider an 80% scale front wing when steady-state cornering with radii ranging from 60m to 7.5 m, and yaw angles ranging from 1.25° to 10°. …
Aerodynamic Testing And Development Of Sunswift Eve, Simon Ambrose, Graham Doig
Aerodynamic Testing And Development Of Sunswift Eve, Simon Ambrose, Graham Doig
Aerospace Engineering
The current understanding of the aerodynamic performance of Sunswift’s solar-electric race car eVe is limited, despite the design and manufacture of the vehicle in 2012-13. This paper describes an investigation into the aerodynamic behaviour of the vehicle and details the successive design and development of drag minimisation strategies. A study of the external airflow around the vehicle was undertaken through a computational fluid dynamics analysis, with validation offered through the results of real-world track testing. Particular reference is made to the Sunswift team’s successful long-range electric vehicle land speed record attempt on 23 July 2014. A predicted 10% reduction in …