The present numerical study is to understand the effect of air tabs located at the exit of a convergent nozzle on the spreading and mixing characteristics of correctly expanded sonic primary jet. Air tabs used in this study are two secondary jets issuing from constant diameter tubes located diametrically opposite at the periphery of the primary nozzle exit, normal to the primary jet. Two air tabs of Mach numbers 1.0 to 1.4, in steps of 0.1 are considered in this study. The mixing modification caused by air tabs are analysed by considering the mixing of uncontrolled (free) primary jet as a reference. Substantial enhancement in jet mixing is achieved with Mach 1.4 air tabs, which results in 80 % potential core length reduction. The total pressure profiles taken on the plane (YZ) normal to the primary jet axis, at various locations along the primary jet centreline revealed the modification of the jet cross sectional shape by air tabs. The stream-wise vortices and bifurcation of the primary jet caused by air tabs are found to be the mechanism behind the enhanced jet mixing.

中文翻译：

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带有空气翼片的正确扩展声波射流的研究

目前的数值研究是为了了解位于会聚喷嘴出口处的空气突片对正确膨胀的声速一次射流的扩散和混合特性的影响。在这项研究中使用的空气导板是从直径恒定的管子中喷出的两个次级射流，这些直径在初级喷嘴出口的外围沿直径方向相对，与初级射流垂直。在此研究中考虑了两个马赫数为1.0到1.4的马赫数，步长为0.1。通过将不受控制的（自由）主射流的混合作为参考来分析由空气标签引起的混合变化。Mach 1.4空气接头可实现射流混合的显着增强，从而可减少80％的潜在铁芯长度。在垂直于主射流轴的平面（YZ）上获取的总压力曲线，沿主喷射中心线的各个位置的箭头显示出通过空气翼片对喷射横截面形状的修改。人们发现，由气流产生的主射流沿流方向的漩涡和分叉是增强射流混合的机制。