Experimental analysis on oscillations of vortex breakdown location over delta wing
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摘要: 在水槽中和风洞中分别进行了流动显示和动态测压实验,目的是研究三角翼前缘涡破裂点的脉动现象.对流动显示图片中涡的破裂点位置进行统计和频谱分析,表明破裂点振荡存在双主频特征,位于0.07位置的主频对应着螺旋—泡—螺旋的转化过程,位于0.2~0.4之间的主频对应着螺旋形态破裂本身的小幅振动.对统计的破裂点位置数据做低通滤波后进行相关性分析,还表明了三角翼左右2个前缘涡的破裂点位置信号具有负相关性.进行三角翼表面动态压力测量,对压力数据低通滤波后做相关性分析,发现相同的一条前缘涡的动态压力信号在整个翼面上都具有高度的相关性.Abstract: Experiments of flow visualization and dynamic pressure measurement were carried out in a water channel and a wind tunnel respectively to research oscillations of the vortex breakdown location over delta wings. Based on statistics and spectral analysis location of vortex breakdown on video picture of flow visualization , result shows that there are two nondimensional primary frequencies. One of them is equal to 0.07 which is a transition frequency of spiral-bubble-spiral form of vortex breakdown, the other primary frequency is at 0.2~0.4 which is the oscillation frequency of spiral breakdown location with smaller amplitude. By correlation analysis of statistical breakdown location data it indicates that there is a negative correlation between signals of left and right vortex breakdown location after low pass filter. Based on dynamic pressure measurement of different station along wing surface under the identical vortex, it is found that there is a strong positive correlation between oscillation signals of pressure by low pass filter.
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Key words:
- delta wing /
- vortex /
- breakdown location /
- oscillations /
- correlation
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