Abstract The effects of jet pulsation intensity on the flow and dispersion characteristics of dual parallel plane jets were experimentally studied. The jet pulsations were generated by acoustic excitations. The laser-light-sheet-assisted smoke flow visualization method was used to study the flow evolution processes. The lateral spreading characteristics of the jets were measured using the binary edge detection method. A hotwire anemometer was used to measure the velocity pulsations, mean velocities, turbulence intensities, and Lagrangian turbulent length and time scales. The dispersion characteristics of the jet fluids were measured by the tracer-gas concentration detection method. The jet Reynolds number and excitation Strouhal number were fixed at 600 and 0.106, respectively. The jet pulsation intensities were varied from 0 to 1.6. As the jets were pulsed, the turbulence intensity, lateral spread width, and jet fluid dispersion capability markedly increased compared with those of the non-pulsed jets. The larger the pulsation intensity was, the higher the turbulence intensity, lateral spread width, and jet fluid dispersion. The Lagrangian time and length scales of the turbulent eddies decreased as the jet pulsation intensity increased because the mushroom-shaped structures generated by the jet pulsations broke up into small turbulent eddies caused by the strong vortex-stretching effect.

中文翻译：

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脉动强度对脉冲双平面射流流动和弥散的影响

摘要 实验研究了射流脉动强度对双平行平面射流流动和弥散特性的影响。射流脉动是由声学激发产生的。激光光片辅助烟流可视化方法用于研究流动演变过程。使用二元边缘检测方法测量射流的横向扩展特性。使用热线风速计测量速度脉动、平均速度、湍流强度和拉格朗日湍流长度和时间尺度。采用示踪气体浓度检测法测量射流流体的弥散特性。射流雷诺数和激发斯特劳哈尔数分别固定为 600 和 0.106。射流脉动强度在 0 到 1.6 之间变化。与非脉冲射流相比，随着射流的脉动，湍流强度、横向扩展宽度和射流流体扩散能力显着增加。脉动强度越大，湍流强度、横向扩展宽度和射流扩散越大。湍流涡旋的拉格朗日时间尺度和长度尺度随着射流脉动强度的增加而减小，这是因为射流脉动产生的蘑菇形结构在强烈的涡旋拉伸作用下分裂成小的湍流涡流。