Numerical Investigation of Low Aspect Ratio Wings at Low Reynolds Numbers

The presented work is centered on the evaluation of Micro or Mini Air Vehicles (MAV) that have been automatically designed and manufactured. An in-house developed design framework uses several coupled computer software's to generate the geometric design in CAD, a well as list of off the shelf components for the propulsion system, and computer code for autonomous flight ready to upload in the intended autopilot. The paper describes the experiences made so far regarding automation of the design process and of manufacturing. Furthermore, it presents results from evaluation and analysis of the optimization algorithm and flight testing, and from continuing work with the framework to achieve deeper understanding of the process and to fine-tune the design automation performance. The flight data is correlated to the predicted performances to validate the models and design process.

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“…Work is being done to better take these effects in to consideration. Inspiration comes from Cosyn 5 and Lupo et. al.…”

Section: B Aerodynamic Analysismentioning

confidence: 99%

Evaluation of Automatically Designed Micro Air Vehicles and Flight Testing

Amadori

Lundström

Krus

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…On the numerical side, two-dimensional simulations around translating wings were performed by Hamdani & Sun (2000). Also, studies by Mittal & Tezduyar (1995) and Cosyn & Vierendeels (2006) considered the three-dimensional flows around translating low-aspect-ratio planforms but focused mostly on those at low angles of attack. For wings at post-stall angles of attack, unsteady separated flows and vortex dynamics behind low-aspect-ratio wings in pure translation are still not well documented.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional flows around low-aspect-ratio flat-plate wings at low Reynolds numbers

2009

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Three-dimensional flows over impulsively translated low-aspect-ratio flat plates are investigated for Reynolds numbers of 300 and 500, with a focus on the unsteady vortex dynamics at post-stall angles of attack. Numerical simulations, validated by an oil tow-tank experiment, are performed to study the influence of aspect ratio, angle of attack and planform geometry on the wake vortices and the resulting forces on the plate. Immediately following the impulsive start, the separated flows create wake vortices that share the same topology for all aspect ratios. At large time, the tip vortices significantly influence the vortex dynamics and the corresponding forces on the wings. Depending on the aspect ratio, angle of attack and Reynolds number, the flow at large time reaches a stable steady state, a periodic cycle or aperiodic shedding. For cases of high angles of attack, an asymmetric wake develops in the spanwise direction at large time. The present results are compared to higher Reynolds number flows. Some non-rectangular planforms are also considered to examine the difference in the wakes and forces. After the impulsive start, the time at which maximum lift occurs is fairly constant for a wide range of flow conditions during the initial transient. Due to the influence of the tip vortices, the three-dimensional dynamics of the wake vortices are found to be quite different from the two-dimensional von Kármán vortex street in terms of stability and shedding frequency.

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“…Work is being done to better take these effects in to consideration. Inspiration comes from Cosyn 6 and Lupo et. al.…”

Section: B Aerodynamic Analysismentioning

confidence: 99%

Automation of Design and Prototyping of Micro Aerial Vehicle

Lundström

Amadori

Krus

2009

47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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The presented work is centered on the automation of the design process of Micro or Mini Aerial Vehicles (MAV). A design optimization framework that links together a CAD system for airframe design and a panel code for aerodynamic evaluations has been developed. This paper is based on research and results previously published by the research team. It describes the experiences made so far, and demonstrates with a case study, how fully automated design is indeed possible. The user is required to enter the initial requirements into the system that will then optimize the MAV design. Both the geometry and the propulsion system are taken into account. Finally, a 3D printer is used for manufacturing of the aircraft. The optimization comprises both discrete and continuous variables. Validation of common propulsion system models is also presented.

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Numerical Investigation of Low Aspect Ratio Wings at Low Reynolds Numbers

Cited by 14 publications

References 6 publications

Evaluation of Automatically Designed Micro Air Vehicles and Flight Testing

Evaluation of Automatically Designed Micro Air Vehicles and Flight Testing

Three-dimensional flows around low-aspect-ratio flat-plate wings at low Reynolds numbers

Automation of Design and Prototyping of Micro Aerial Vehicle

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