Experimental Study on the Flow Patterns of a Simplified Aircraft Model at High Angles of Attack
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摘要: 在水洞中应用染色液流动显示技术对某型号飞机简化模型机头流动状况随攻角和来流速度的演化进行了观测和分析.实验结果表明,在本实验条件下,对于不同的来流速度或雷诺数,每种流动现象所对应的攻角确实发生了变化,说明雷诺数的影响确实存在;另外,对自由转捩条件下,俯仰力矩曲线在α=35°~70°之间很分散的风洞实验结果进行了初步的解释:α=35°基本上对应于边条涡非对称破裂的开始;而α=70°则对应于机头迎风面流动向前、向后的临界点.Abstract: The dye-injection flow visualization technique has been used to study the changes of flow patterns for a simplified aircraft model with the variation of angles of attack and the incoming flow velocity in a water tunnel. In this experiment, the changes of flow patterns do not have essential difference at several incoming flow velocities, but the variation of the relevant angles of attack occurs indeed, which means that there exists the Re-dependence. Moreover, for the scatter of the experimental pitch-up moment curve in the case of natural transition, the explanation has been made. α=35° corresponds the start of asymmetric breakdown of the strake vortex and α=70° is the critical point of the flow forth and back in the up wind side of the nose.
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Key words:
- vortex flow /
- flow visualization /
- separated flow /
- high angle of attack /
- simplified aircraft model
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[1] 梅尔兹科奇 W(德)著.流动显示[M].黄素逸,王志国,张浩然译.北京:科学出版社,1991. [2]王晋军雷诺数对三角翼绕流的影响[J].实验力学,1998,13(4):497~501 [3]Malcolm G N,Nelson R C.Comparison of water and wind tunnel flow visualization results on a generic fighter configuration at high angle of attack .AIAA-87-2423,1987.
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