激波和剪切层相互作用下的超音速射流

Supersonic jet with interaction between shock and shear layers

欠膨胀超音速射流处于螺旋模式下的中度欠膨胀时 ,其入射剪切层的激波具有很高强度 ,激波和剪切层发生了强烈的相互作用 ,远场辐射的拢动波出现了大间隔、交错的上下行类似螺旋锥面波形图像 ,该扰动波具有很强的向上游传播的指向性 ,导致上游噪声高于垂直喷嘴方向的声压级 .而在相对压比较低的低度欠膨胀情况下 ,或高压比下的高度欠膨胀的情形 ,入射剪切层激波强度相对较弱 ,远场辐射没有大间隔。

For moderately under\|expanded jets,the schlieren visualization reveals that shock cells become intensified and stronger interaction between shock and shear layer occurs.The resulting disturbance waves with the large alternating intervals propagate in the upstream direction.The existence of the upstream disturbances makes the upstream sound pressure level greater than that of directivity normal to the nozzle exit plane.Under low under\|expansion,the intensities of the interaction between shock cells and shear layer are low,even at large pressure ratios.