PIV (Particle Image Velocimetry) experiments were conducted to reveal the influence of the Reynolds number (Re), position, and inclination angle of a slit vent on the overall flow dynamics characteristics of slit-vent cylinders. The flow mechanism of the slit vent was studied based on the quantitative evaluation of the periodic shedding vortex transformations. The experimental results indicated that the slit vent could produce a strong effect of blowing and suction on the boundary layer if the slit-vent position was in front of the flow separation point for the base cylinder. The effect of the blowing and suction caused the Kármán vortex street (KVS) to occur much earlier and strengthened the vortex shedding for the 120° and 180° slit-vent cylinders. The St values of the 180° slit-vent cylinders were least sensitive to Re as compared with the other cylinder types with Re = 2000 ∼ 5400. With the slit-vent inclination angle β varying in the range of 80°–90°, the St values of the 180° slit-vent cylinder were around 0.225 and exhibited the greatest stability.

进行PIV（颗粒图像测速）实验以揭示雷诺数（Re），狭缝排气孔的位置和倾斜角度对狭缝排气筒整体流动动力学特性的影响。基于对周期性脱落涡转化的定量评估，研究了狭缝出口的流动机理。实验结果表明，如果狭缝排气孔的位置在底缸的分流点之前，狭缝排气孔会对边界层产生强烈的吹吸作用。吹气和吸气的作用使Kármán涡街（KVS）发生得更早，并增强了120°和180°裂口气缸的涡流脱落。β在80°–90°范围内变化，180°狭缝排气筒的St值约为0.225，并显示出最大的稳定性。