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DYNAMIC TUNING OF INSECT AND BIRD WINGS AND COPEPOD AND DAPHNIA APPENDAGES
Citation:
Frick, W E., D. L. Denton, AND M C. Barber. DYNAMIC TUNING OF INSECT AND BIRD WINGS AND COPEPOD AND DAPHNIA APPENDAGES. Presented at 2004 Ocean Research Conference, Honolulu, HI, February 15-20, 2004.
Impact/Purpose:
A main objective of this task is to combine empirical and physical mechanisms in a model, known as Visual Beach, that
â— is user-friendly
â— includes point and non-point sources of contamination
â— includes the latest bacterial decay mechanisms
â— incorporates real-time and web-based ambient and atmospheric and aquatic conditions
â— and has a predictive capability of up to three days to help avert potential beach closures.
The suite of predictive capabilities for this software application can enhance the utility of new methodology for analysis of indicator pathogens by identifying times that represent the highest probability of bacterial contamination. Successful use of this model will provide a means to direct timely collection of monitoring samples, strengthening the value of the short turnaround time for sampling. Additionally, in some cases of known point sources of bacteria, such as waste water treatment plant discharges, the model can be applied to help guide operational controls to help prevent resulting beach closures.
Description:
Compressible flow theory suggests, and dimensional analysis and growing empirical evidence confirm that, to aid flight, many insects and even some birds, notably hummingbirds, tune their wing-beat frequency to a corresponding characteristic harmonic frequency of air. The same property that governs the physics of acoustics, the compressibility of air and water, helps insects to fly and small aquatic animals to swim and capture food. The basic principle is simple, all the animal has to do, for example, to hover, is to beat its wings at exactly half the natural compressive frequency of air, or water. To use insect flight to help understand the principle, if at the tuned frequency the insect achieves maximum compression below the wing at mid downstroke, then the elastic properties of air will achieve maximum recoil decompression at the bottom of the stroke followed by maximum compression on the subsequent up stroke. The opposite is true above the wings. Albeit not as great as on the downstroke, the animal gets a free boost on the upstroke. The phenomenological governing variables are identified and the wing-beat frequency is derived from dimenstional analysis and physical reasoning.