The impact of aspect ratio on aerodynamic performance and flow separation behavior of a model wing composed from different profiles

Abstract

In this study the impact of aspect ratio on the aerodynamic performances and flow separation behavior were investigated on a model wing made up four different profiles used to the wing of the Boeing 737-Classic aircrafts. The experiments were carried out in a wind tunnel with low speed at different angles of attack ranging from -4° to 40° and at the 200,000 Reynolds number on wing models having different aspect ratios (0.7-1.3).It was observed from the experiments and numerical studies that the changing of the aspect ratio affected the drag and lift and flow separation. The highest lift/drag ratio has been measured from the wing having aspect ratio of 1.3 at angle of attack of 70. Moreover, the airflow was flowed as laminar in the areas near the middle of the wing until angle of attack of 240. But, the flow was disturbed at wing tip due to vortex. The separation bubbles have been seen at 24°-320 for all aspect ratios. In addition, the increase of angle of attack caused the bubbles form clearly for 1.1 and 1.3 aspect ratios. Finally, the increases in aspect ratio and in angle of attack have been triggered flow separation.