Numerical Investigation of Circulation Control Airfoils

1. Numerical Investigation of Circulation Control Airfoils Byung-Young Min, Warren Lee Robert Englar, and Lakshmi N. Sankar School of Aerospace Engineering Georgia Institute of Technology, Atlanta, GA, 30332-1550 

2. Outline Background Research Objectives Configurations studied Mathematical and Numerical Formulation Results and Correlation with Experiments Effects of formal spatial accuracy Effects of jet turbulence intensity Effects of grid density Effects of the inclusion of plenum and nozzle geometry in the model Effects of turbulence model Conclusions and recommendations

3. Background Noise pollution from the large aircraft has become a major problem that needs to be solved. NASA proposed a plan to reduce the noise by a factor of four (20dB) by 2025. A major source of large aircraft airframe noise during take-off and landing is the high-lift system - namely flaps, slats, associated with flap-edges and gaps. The high-lift system also contains many moving parts, which add to the weight of the aircraft, and are costly to build and maintain. These devices for generating high lift are necessary for large aircraft that use existing runways. In recent years, there has been an increasing demand for very large aircraft due to the heavy traffic. But at the same time, the noise pollution of this kind of aircraft becomes a serious problem. NASA proposed a plan to double aviation system capacity while reducing perceived noise by 10dB by 2011, and to triple system capacity while reducing perceived noise by 20dB by 2025. The aircraft noise is divided into two categories based on the noise sources, the jet engine noise and the airframe noise. The jet engine noise has already been greatly reduced by the use of improved high bypass-ratio turbofan engines. However, the airframe-generated noise can be the dominant component of the total noise level, especially during landing approach when the engines are at a relatively low power setting.. When aircraft taking-off and landing, a major airframe noise source is the high-lift systems -- ie, the flaps, slats, associated with flap-edges and gaps etc. The high-lift system also ……. However, these devices of …….In recent years, there has been an increasing demand for very large aircraft due to the heavy traffic. But at the same time, the noise pollution of this kind of aircraft becomes a serious problem. NASA proposed a plan to double aviation system capacity while reducing perceived noise by 10dB by 2011, and to triple system capacity while reducing perceived noise by 20dB by 2025. The aircraft noise is divided into two categories based on the noise sources, the jet engine noise and the airframe noise. The jet engine noise has already been greatly reduced by the use of improved high bypass-ratio turbofan engines. However, the airframe-generated noise can be the dominant component of the total noise level, especially during landing approach when the engines are at a relatively low power setting.. When aircraft taking-off and landing, a major airframe noise source is the high-lift systems -- ie, the flaps, slats, associated with flap-edges and gaps etc. The high-lift system also ……. However, these devices of …….