Journal of the Korean Society for Aeronautical & Space Sciences (한국항공우주학회지)

The Korean Society for Aeronautical and Space Sciences (한국항공우주학회)
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Aerodynamic Study on Phase Difference of Fore-and Hind-wing of a Dragonfly-type Model

잠자리 유형 모델의 앞,뒤 날개 위상차에 대한 공력연구

  • Published : 2006.11.30
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Abstract

Unsteady aerodynamic force measurements were carried out in order to investigate the effects of phase difference of a dragonfly-type model with two pairs of wing. A load-cell was employed to measure the aerodynamic force generated by a plunging motion of the dragonfly-type model. The dragonfly-type model has a dynamic similarity with real one, and incidence angles of fore- and hind-wing are 0° and 10°, respectively. Other experimental conditions are as follows: The freestream velocity was 1.6 m/sec and corresponding chord Reynolds number was 2.88×103, and phase differences of fore- and hind-wing were 0°, 90°, 180° and 270°. The variation of aerodynamic coefficients during one cycle of the wing motion is presented. Results show that the lift is generated during the downstroke motion and the drag generated during the hind-wing‘s downstroke motion with the lift generation.

비정상 공기력 측정이 두 쌍의 날개를 갖는 잠자리 유형 모델의 위상차에 따른 효과를 조사하기 위하여 수행되었다. 잠자리 유형 모델의 플런징 운동에 의하여 발생된 공기역학적인 힘을 측정하기 위하여 로드셀을 사용하였다. 본 잠자리 유형 모델은 실제 잠자리와 동역학적으로 상사하며, 앞뒤날개는 각각 0°의 10°의 붙임각(incidence angle)을 가지고 있다. 다른 실험 조건은 다음과 같다. 자유류의 속도는 1.6 m/sec이고, 이와 관련된 시위 레이놀즈수 2.88×103이며, 앞뒤날개의 위상차는 각각 0°, 90°, 180°, 그리고 270°이다. 잠자리 유형 날개의 한 주기 동안 공기역학적 계수의 변화가 제시되었다. 연구 결과는 잠자리 유형 모델의 양력은 앞뒤날개가 downstroke 운동을 수행할 때 발생되며, 뒷날개가 downstroke 운동과정을 수행하면 양력 발생과 함께 항력도 발생한다는 것을 보여준다.

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References

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