An experimental study was conducted on the flow characteristics and turbulence suppression in vertically issued bubbly jets with low void fraction (less than 1%, Re = 3,172). The effect of bubble distributions on the flow characteristics of the bubbly jet was investigated using planar Laser-Induced Fluorescence (PLIF) in the same measurement plane as Particle Image Velocimetry (PIV) for the phase separation. To ensure uniform size of the small bubbles, a bubble generator consisting of small needles was designed and manufactured. Due to the low void fraction, the velocity fields of each phase were successfully obtained. The slip velocity was constant in the far-field of the flow as 2.1 times of the inlet velocity in this study. In the early stage of the jet, there is an acceleration region that is attributed to the buoyancy of bubbles. As the potential core of the bubbly jets collapses, the distribution of bubbles seems to have an annular truncated cone shape, which evolves with the liquid flow structure. Most bubbles are populated the region around the velocity radius of the bubbly jet. Reynolds shear stresses and normal stresses of the dilute bubbly jet generally show smaller magnitudes than those of pure jets, buoyant jets, bubbly jets, and bubbly plumes. The case with higher void fraction (1%, Exp.330) shows similar magnitude of Reynolds axial stresses to jets, but magnitudes of other stresses are similar to the case with lower void fraction (0.66, Exp.320). The results are probably attributed to suppression of turbulence in low-void-fraction condition.

对具有低空隙率（小于 1%，Re = 3,172）的垂直喷射气泡射流的流动特性和湍流抑制进行了实验研究。使用平面激光诱导荧光 (PLIF) 在与用于相分离的粒子图像测速 (PIV) 相同的测量平面中研究气泡分布对气泡射流流动特性的影响。为确保小气泡的大小均匀，设计并制造了由小针组成的气泡发生器。由于空隙率低，成功获得了每一相的速度场。在本研究中，流动远场中的滑移速度恒定为入口速度的 2.1 倍。在射流的早期阶段，有一个归因于气泡浮力的加速区。随着气泡射流潜在核心的坍塌，气泡的分布似乎呈环形截锥形状，并随着液体流动结构演变。大多数气泡聚集在气泡射流速度半径周围的区域。稀释气泡射流的雷诺剪应力和法向应力通常比纯射流、浮力射流、气泡射流和气泡羽流的雷诺剪应力和法向应力小。较高空隙率 (1%, Exp.330) 的情况显示雷诺轴向应力与射流相似，但其他应力的幅度与较低空隙率 (0.66, Exp.320) 的情况相似。结果可能归因于低空隙率条件下湍流的抑制。随液流结构演变。大多数气泡聚集在气泡射流速度半径周围的区域。稀释气泡射流的雷诺剪应力和法向应力通常比纯射流、浮力射流、气泡射流和气泡羽流的雷诺剪应力和法向应力小。较高空隙率 (1%, Exp.330) 的情况显示雷诺轴向应力与射流相似，但其他应力的幅度与较低空隙率 (0.66, Exp.320) 的情况相似。结果可能归因于低空隙率条件下湍流的抑制。随液流结构演变。大多数气泡聚集在气泡射流速度半径周围的区域。稀释气泡射流的雷诺剪应力和法向应力通常比纯射流、浮力射流、气泡射流和气泡羽流的雷诺剪应力和法向应力小。较高空隙率 (1%, Exp.330) 的情况显示雷诺轴向应力与射流相似，但其他应力的幅度与较低空隙率 (0.66, Exp.320) 的情况相似。结果可能归因于低空隙率条件下湍流的抑制。浮力喷射、气泡喷射和气泡羽流。较高空隙率 (1%, Exp.330) 的情况显示雷诺轴向应力与射流相似，但其他应力的幅度与较低空隙率 (0.66, Exp.320) 的情况相似。结果可能归因于低空隙率条件下湍流的抑制。浮力喷射、气泡喷射和气泡羽流。较高空隙率 (1%, Exp.330) 的情况显示雷诺轴向应力与射流相似，但其他应力的幅度与较低空隙率 (0.66, Exp.320) 的情况相似。结果可能归因于低空隙率条件下湍流的抑制。