An experimental investigation has been carried out to examine the effectiveness of air-tabs in controlling the subsonic and correctly expanded sonic jets. The primary/main-jet was controlled by the air-tab (control-jet) of different diameter and exit Mach numbers. The Mach number decay along the jet centerline and the Mach number profiles along and normal to the air-tabs were determined from the measured Pitot pressures. Increase in mass flow rate of the control-jet or air-tab results in reduced potential core length, thereby better mixing. The distortion introduced by the air-tab increases with increase in Mach number, mass flow rate and decrease in diameter of the air-tab. A 20% reduction in main-jet local Mach number can be brought about by a control-jet mass flow of 4.04% of the main-jet mass flow from the smaller air-tab (d/D = 1/8.33), whereas the same reduction with larger control nozzles (d/D = 1/6.25 and 1/5.0) requires a control-jet mass flow of 7.0% and 12.6%, respectively. Moreover, the air-tabs with smaller diameter, exhibit higher distortion of the jet and resultant increase in jet mixing. Therefore, air-tab of smaller diameter was found to perform better than the higher air-tab diameters. A combination of, Mach number ratio, mass flow ratio and diameter ratio, was found to have a direct influence in the jet spread and mixing.
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机译：已经进行了一项实验研究，以检查空气标签在控制亚音速和正确扩展的音速射流中的有效性。主喷嘴/主喷嘴由不同直径和出口马赫数的空气标签（控制喷嘴）控制。从测得的皮托管压力确定沿喷射中心线的马赫数衰减和沿空气标签并垂直于空气标签的马赫数分布。控制喷嘴或空气接头的质量流量增加会导致潜在的铁芯长度减少，从而实现更好的混合。随着马赫数的增加，质量流量的增加以及空气舌片直径的减小，空气舌片引起的变形增加。主喷嘴的局部马赫数减少20％，这是因为较小的空气翼片（d / D = 1 / 8.33）产生的主喷嘴质量流量的4.04％，而主喷嘴的局部马赫数减少了（d / D = 1 / 8.33）。如果使用较大的控制喷嘴（d / D = 1 / 6.25和1 / 5.0）进行同样的减小，则控制喷嘴的质量流量分别为7.0％和12.6％。此外，具有较小直径的空气突片表现出较高的射流变形并因此增加了射流混合。因此，发现直径较小的空气表比直径较大的空气表更好。发现马赫数比，质量流量比和直径比的组合对射流的扩散和混合具有直接影响。
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