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하이브리드 방법을 이용한 비행 중 비행체 음향하중 예측에 관한 연구

A study on the acoustic loads prediction of flight vehicle using computational fluid dynamics-empirical hybrid method

  • 투고 : 2018.05.17
  • 심사 : 2018.07.19
  • 발행 : 2018.07.31

초록

본 논문에서는 비행 중 비행체 표면에 작용하는 음향하중 예측을 수행하였다. 비행 중 음향하중은 비행체 표면의 압력 변동에 의해 발생한다. 기존의 비행 중 음향하중 예측방법은 반경험적 방법으로 이론과 실험 결과를 기반으로 도출한 경험식을 활용한다. 하지만 경험식의 입력 값으로 사용되는 비행체 주변 유동특성 및 경계층 파라미터를 매번 실험을 통해 얻는 것에는 한계가 있다. 따라서 본 논문에서는 전산유체해석(Computational Fluid Dynamics, CFD) 결과를 반경험적 방법과 혼합하는 하이브리드 방법을 이용하여 비행 중 비행체에 작용하는 음향하중을 예측하였다. Cone-cylinder-flare 형상 비행체에 대해 아음속, 천음속, 초음속, 최대동압도달(Maximum dynamic pressure, Max-q) 시점의 비행 환경에 대한 음향하중 예측을 수행하였다. 하이브리드 방법 적용 시 전산유체해석결과를 기반으로 한 경계층 끝단 영역 판단 방법에 대해 비교하였고 여러 연구자에 의해 제시된 경험식에 따른 음향하중 예측결과를 비교하였다.

This paper performed the prediction of the acoustic loads applied to the surface of the flight vehicle during flight. Acoustic loads during flight arise from the pressure fluctuations on the surface of body. The conventional method of predicting the acoustic loads in flight uses semi-empirical method derived from theoretical and experimental results. However, there is a limit in obtaining the flow characteristics and the boundary layer parameters of the flight vehicle which are used as the input values of the empirical equation through experiments. Therefore, in this paper, we use the hybrid method which combines the results of CFD (Computational Fluid Dynamics) with semi-empirical methods to predict the acoustic loads acting on flight vehicle during flight. For the flight vehicle with cone-cylinder-flare shape, acoustic loads were estimated for the subsonic, transonic, supersonic, and Max-q (Maximum dynamic pressure) condition flight. For the hybrid method, two kind of boundary layer edge estimation methods based on CFD results are compared and the acoustic loads prediction results were compared according to empirical equations presented by various researchers.

키워드

참고문헌

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