Quantification of canard and wing interactions using spatial correlation velocimetry

Fawcett, P. A.; Funk, Robert; Komerath, Narayanan

doi:10.2514/6.1992-2687

Cited by 6 publications

(5 citation statements)

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“…10. Here, a sophisticated dual-intensified camera system is used to capture the flow patterns over a wing-canard configuration in close interaction 17 . The canard moves to various positions relative to the wing, causing effects which are clearly visible on the videotape.…”

Section: Velocity Extraction From Video Imagesmentioning

confidence: 99%

Image processing in the undergraduate fluid dynamics laboratory

Komerath

1992

17th Aerospace Ground Testing Conference

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Easy access to video imaging, digital frame grabbing and image processing technology has opened up exciting opportunities in fluid mechanics education. This paper presents several examples of student work, and discusses new curricula based on these new developments. Complex, unsteady flows can now be quantified using multi-dimensional techniques. Image sequences can be stored and used in problem-solving. The author extrapolates these experiences to the hypothesis that image-based curricula can revolutionize fluid dynamics education, and permit the undergraduate to become familiar with fluids engineering technology, exploiting unsteady flows. INTRODUCTION In the hectic environment of a modern engineering school, it is difficult to conduct laboratory experiments suitable for hands-on participation by large classes. Advances in computational capabilities have created the demand for (and the relatively easy solution of providing) increased attention to computational fluid dynamics. At the same time, the time available to teach fluid dynamics is compressed by demands for "broader" curricula, advances in other fields, and the pressure to reduce the total hours required for the first degree. The laboratory course is an easy candidate for cuts, as Shop classes were in the past. There are two undesirable results: 1) The typical undergraduate gets very little exposure to the beauty, variety, and realities of fluid dynamics, instead seeing a collection of smart techniques for solving differential equations "governing" steady, laminar, attached, single-component flows of perfect gases over streamlined shapes. Sometimes this occurs at the expense of physical insight, and of students who might otherwise become intuitive leaders in fluid dynamics. 2) Prevalent opinion holds that the future is all in CFD, and that hardware experiments, if done at all, are purely for "code validation", with attention restricted to those phenomena which are already known and modeled in the codes.

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Section: Velocity Extraction From Video Imagesmentioning

confidence: 99%

Image processing in the undergraduate fluid dynamics laboratory

Komerath

1992

17th Aerospace Ground Testing Conference

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“…Thus it is now possible to measure velocity field histories while the configuration is being continuously varied 12 , or even during high-rate, largeamplitude transient maneuvers 13 . Over the past two years, the technique has progressed from solid surfaces and water flows (50mm x 50mm, 150mm/sec, Ref.…”

Section: Velocity Measurementsmentioning

confidence: 99%

“…In Ref. 12, we have shown a detailed history of the velocity field over the wing/canard configuration measured while the canard was continuously changing position.…”

Section: Geometric Variationmentioning

confidence: 99%

“…12 (600mm x 400mm, 10 m/s). Implementation of SCV begins with the grabbing and digitizing of two corresponding frames separated by a known time delay.…”

Section: Velocity Measurementsmentioning

confidence: 99%

“…Successive images separated by a time delay on the order of 50-90 micro-seconds were analyzed to obtain velocity fields as detailed in Ref. 12.…”

Section: Geometric Variationmentioning

confidence: 99%

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A multi-diagnostic approach to testing V/STOL craft

Foley

Funk

Fawcett

et al. 1992

17th Aerospace Ground Testing Conference

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The interactive aerodynamics of new V/STOL designs require a new approach to ground testing, where multiple properties are measured both on and away from surfaces during continuous changes in test parameters. Using a set of experiments of increasing complexity, a new capability is demonstrated for capturing surface pressure, velocity fields and vortex flow features over a range of test parameters. Two-dimensional velocity fields are captured over a full-scale UH-1 helicopter stabilator, a wing/canard configuration, and under the hub of a rotor in forward flight. Surface pressures and vortex flow features are captured over a wing/rotor configuration. Short tunnel run-times are achieved at the expense of large computational postprocessing resources. It is shown that such experiments can be performed while the configuration geometry and flow conditions are continuously varied through a wide range of parameters. This experiment led to the discovery and capture of massive flow separation caused by vortex interaction on wings at moderate angles of attack, large-scale deflection of vortex wake trajectories by wake/wing interaction, unsteady flows over wings generated by canard interaction, and quasisteady separation phenomena caused by the difference in time scales between separation and reattachment.

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