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NACA 0012 에어포일의 경계층 거동이 근접 후류에 미치는 영향
양재훈,김동하,장조원,Yang, Jae-Hun,Kim, Dong-Ha,Chang, Jo-Won 한국항공운항학회 2006 한국항공운항학회지 Vol.14 No.4
An experimental study was carried out in order to investigate the influence of boundary layer behavior on the near-wake at low Reynolds numbers. An X-type hot-film probe(55R51) was used to measure the near-wake of an NACA 0012 airfoil at static angles of attack ${\alpha}=0^{\circ}$, $3^{\circ}$, and $6^{\circ}$, and the Reynolds numbers Re=2.3${\times}10^4$, 3.3${\times}10^4$, and 4.8${\times}10^4$. The results of the study show that the characteristics of the boundary layer on the airfoil surface have a close relationship with the mean velocity and turbulence intensity profiles of a near-wake. Therefore, the development of the boundary layer, the position of the separation point, and the existence and non-existence of reattachment on the airfoil surface were represented by the differences in mean velocity and turbulence intensity profiles of the near-wake.
저 레이놀즈수에서 정지된 에어포일의 경계층 및 근접 후류 가시화 연구
양재훈(Jae Hun Yang),장조원(Jo Won Chang) 한국가시화정보학회 2006 한국가시화정보학회지 Vol.4 No.2
A visualization study on the boundary layer and near-wake of an NACA 0012 airfoil was conducted in order to investigate the influence of boundary layer behavior on the near-wake at low Reynolds numbers. The present study is investigated at static angles of attack α=0°, 3°, 6° and Re=2.3×10⁴, 3.3×10⁴, 4.8×10⁴ by using a smoke-wire technique. The results of this study show that the laminar boundary layer on the airfoil surface is attached to the surface at α=0°, and that laminar separation of boundary layer on the airfoil surface occurs at α=3°. Furthermore, reattachment of the boundary layer occurs in the case of α=6°. In the current study, the location of the laminar separation point moves upstream as the Reynolds number and the angle of attack increase.
양재훈(Jae-Hun Yang),장조원(Jo-Won Chang) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.10
저 레이놀즈수에서 NACA 0012 에어포일의 경계층 거동에 관한 연구가 터빈 블레이드와 초소형 비행체에서 적용될 수 있는 경계층을 파악하기 위하여 수행되었다. 레이놀즈수 Re=2.3×10⁴, 3.3×10⁴, 4.8×10⁴과 정적 받음각 α=0˚, 3˚, 6˚에서 경계층을 측정하기 위해 열선 풍속계가 사용되었다. 연구결과는 정적 받음각 0˚에서는 층류 경계층이 에어포일 표면에 부착되며, 정적 받음각 3˚에서는 경계층 층류 분리가 발생된 것을 보여준다. 더욱이 본 연구에서 경계층 재부착 현상은 정적 받음각 6˚에서 레이놀즈수 3.3×10⁴와 4.8×10⁴에서 발생된다. A study on the boundary layer behavior of an NACA 0012 airfoil at low Reynolds numbers was investigated in order to gain knowledge of a boundary layer that might be employed in a turbine blade and MAVs. A hot-wire anemometer was used to measure the boundary layer of an NACA 0012 airfoil at static angles of attack α=0˚, 3˚, and 6°, and Reynolds Numbers Re=2.3×10⁴, 3.3×10⁴, and 4.8×10⁴. The results of this study show that the laminar boundary layer on the airfoil surface is attached to the surface at α=0˚, and the laminar separation of the boundary layer on the airfoil surface occurs at α=3˚. Furthermore, the reattachment of the boundary layer in the present study occurs for the cases of Re=3.3×10⁴ and Re=4.8×10⁴ at α=6˚.