Investigation on Aerodynamics and Flow Properties of a Low-Aspect-Ratio Thin-Plate Wing at Low Reynolds Number

• Main Authors: Chung-Hai Chen, 陳崇海
• Other Authors: Fei-Bin Hsiao
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/24481371667645704010

碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 96 === This thesis studies the flow structures of wing tip vortex on thin-plate wing at different angles of attack. The thin-plate wing model with AR = 1 was operated at free-stream velocity of 13m/s, corresponding to chord-based Reynolds number of 8×10^4. The wing model was tested at the angles of attack ranging from 10° to 50° in these experiments. The flow properties were obtained by streamwise and spanwise mean and fluctuation velocities measured by a cross-type hot wire anemometer. Experimental results show that the velocity profile of the wing of AR = 1 is very different with that of AR = 2 and 3. At AR = 1 the stall angle is after AOA = 40°, but the stall angle of AR = 2 and AR = 3 is about AOA = 20°, these result are in good agreement with previously published researches. More detail flow properties of AR = 1 was investigated. Experimental results indicate that the vortex size and the distance between vortex core and trailing edge increases as angle of attack increases. The area of highly affected region increases as angles of attack increases, reaches the maximum at AOA = 35°, and decreases as angles of attack increases furthermore. From the contours of streamwise and spanwise mean velocities, the flow field can be divided into two types. In the first type where the AOA is less than 35°, the vortex core stands at the upper surface of the wing, the vertical component of tip vortex accelerates partially flow field on the upper surface to suppress the flow separation on the upper surface, in this type the affection of tip vortex is getting stronger when angles of attack increases. While in the second type where the AOA is larger than 35°, the vortex core starts to shift away from the root of the wing, and the vortex size continues to grow up with deformed flow structures.