• International Journal of Aeronautical and Space Sciences
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• 제12권2호
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• pp.190-199
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• 2011

Unsteady flow simulations of complete helicopter configurations were conducted, and the flow fields and the aerodynamic interferences between the main rotor, fuselage, and tail rotor were investigated. For these simulations, a three-dimensional flow solver based on unstructured meshes was used, coupled with an overset mesh technique to handle relative motion among those components. To validate the flow solver, calculations were made for a UH-60A complete helicopter configuration at high-speed and low-speed forward flight conditions, and the unsteady airloads on the main rotor blade were compared to available flight test data and other calculated results. The results showed that the fuselage changed the rotor inflow distribution in the main rotor blade airloads. Such unsteady vibratory airloads were produced on the fuselage, which were nearly in-phase with the blade passage over the fuselage. The flow solver was then applied to the simulation of a generic complete helicopter configuration at various flight conditions, and the results were compared with those of the CAMRAD-II comprehensive analysis code. It was found that the main rotor blades strongly interact with a pair of disk-vortices at the outer edge of the rotor disk plane, which leads to high pulse airloads on the blade, and these airloads behave differently depending on the specific flight condition.

• 한국항공우주학회지
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• 제38권6호
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• pp.519-529
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• 2010

본 연구에서는 주로터, 동체, 그리고 꼬리로터를 포함한 UH-60A 전기체 형상에 대한 비정상 유동 해석을 수행하였다. 개발된 로터해석용 유동 해석코드를 이용하여 고속 전진 비행 및 저속 전진비행 조건에 대한 해석을 수행하였으며, 해석코드의 검증을 위해 주로터에서의 비정상 공력 하중을 비행시험 및 타 연구자들의 해석 결과와 비교하였다. 주로터만 존재하는 형상, 주로터와 동체만 존재하는 형상, 그리고 꼬리로터만 존재하는 형상에 대한 해석 결과를 전기체 형상에 대한 해석 결과와 비교함으로써 헬리콥터 각 컴포넌트 간의 공기력 간섭현상을 분석하였다. 동체는 주로터에서 발생하는 내리흐름 분포를 변화시킴으로써 주로터의 수직력 분포를 변화시키는 요인이 됨을 확인하였으며, 주로터 끝단으로부터 발생한 와류와 꼬리로터 블레이드가 충돌함에 따라 강한 간섭현상이 발생함을 확인하였다

• International Journal of Aeronautical and Space Sciences
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• 제11권1호
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• pp.1-9
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• 2010

Numerical simulation of unsteady flows around helicopters was conducted to investigate the aerodynamic interaction of main rotor and other components such as fuselage and tail rotor. For this purpose, a three-dimensional inviscid flow solver has been developed based on unstructured meshes. An overset mesh technique was used to describe the relative motion between the main rotor, and other components. As the application of the present method, calculations were made for the rotor-fuselage aerodynamic interaction of the ROBIN (ROtor Body INteraction) configuration and for a complete UH-60 helicopter configuration consisted of main rotor, fuselage, and tail rotor. Comparison of the computational results was made with measured time-averaged and instantaneous fuselage surface pressure distributions for the ROBIN configuration and thrust distribution and available experimental data for the UH-60 configuration. It is demonstrated that the present method is efficient and robust for the simulation of complete rotorcraft configurations.