实验测量了圆湍射流和不同数目加齿射流流场速度信号,用标准κ-ε模式对实验中对应条件的湍射流流场进行了数值计算。研究了喷口不同数目加齿对自由湍射流多尺度湍涡结构的控制效果。结果表明:加齿改变了湍射流多尺度涡结构能量的空间分布,将射流中心线位置的能量向边界输运。此外,加齿对近场齿尖位置涡结构具有破碎作用,而且在不同流向法向位置还会引起涡的合并和卷吸。
Experimental flow field measurement of the circular and various wedged turbulent jets has been carried out. Simultaneously,standard κ-ε model has been employed in the numerical simulation of the mean flow fields of various turbulent jets corresponding to the measured values. Comparison research has been performed to analyze the fragmentation and enhanced mixing effect of the nozzles with different number of wedge on the multi-scaled turbulent eddy structures in the free jet flow. The experimental and numerical results show that the energy distribution of wedged jets in space is different from that of the circular jet with the energy at the center being transported sidewise. Furthermore, due to the wedges not only the eddy structures at the wedge tines in the near field are broken up, but also the interactions such as eddy structures rejoining and entrainment take place at different locations normal to the flow along the longitudinal development of the jets.