The dynamic mixedness characteristics of a bluff-body stabilized turbulent jet under transverse acoustic excitations were investigated using high-repetition-rate acetone planar laser-induced fluorescence (PLIF) at 7 kHz and multipoint scanning hot-wire measurements. Acetone mixedness imaging was applied for the turbulent jet to assess the interaction between the turbulent jet and the imposed transverse acoustic excitations at a driving frequency of 50 Hz. The high-repetition-rate acetone PLIF images showed that the acetone mixedness distribution swung left and right frequently under the transverse acoustic excitation, and the deflection angle could reach about 6°. The mixedness area of a turbulent jet flow could also be increased by 13.3% when excited by a transverse acoustic wave. Meanwhile, the sequence of instantaneous acetone PLIF images illustrated how the wrinkled edges were generated when acoustic excitations were imposed. The curvature of the acetone PLIF interface showed that the portion of large curvatures increased by 60% after applying an acoustic wave of 123 dB. Multipoint hot-wire measurements further stressed that the turbulent intensity at the transverse acoustic excitation of 123 dB increased to be about 1.3 times the natural turbulence. The proper orthogonal decomposition results showed that the large and small scales of the jet wrinkles both increased with the sound pressure level. RANS transient simulation also implied that distorted velocity streamlines could be achieved inside the turbulent jet due to the transverse acoustic excitation. They could further lead to inhomogeneous convection and increased mixing between the turbulent jet and the surrounding air.

使用 7 kHz 的高重复率丙酮平面激光诱导荧光 (PLIF) 和多点扫描热线测量，研究了在横向声激发下阻流体稳定湍流射流的动态混合特性。将丙酮混合成像应用于湍流射流，以评估湍流射流与驱动频率为 50 Hz 时施加的横向声学激发之间的相互作用。高重频丙酮PLIF图像显示，丙酮混合度分布在横向声激励下左右摆动频繁，偏转角度可达6°左右。当被横向声波激发时，湍流射流的混合区也可以增加 13.3%。同时，瞬时丙酮 PLIF 图像序列说明了在施加声学激励时如何产生褶皱边缘。丙酮 PLIF 界面的曲率显示，在施加 123 dB 的声波后，大曲率的部分增加了 60%。多点热线测量进一步强调，在 123 dB 的横向声学激发下的湍流强度增加到大约是自然湍流的 1.3 倍。本征正交分解结果表明，喷射皱纹的大小尺度均随声压级的增加而增大。RANS 瞬态模拟还表明，由于横向声激励，可以在湍流射流内部实现扭曲的速度流线。