圆环旋转黏性液体射流空间不稳定性研究

摘要

利用线性稳定性理论,进行了液体黏性对不同旋转强度下圆环旋转液体射流空间不稳定性影响的研究.在推导出的三维扰动下具有固体涡核型旋转速度分布的圆环旋转黏性液体射流色散方程的基础上,针对中低速射流,进行了类反对称模式与类对称模式下圆环旋转黏性液体射流的空间不稳定性分析.研究结果表明,对于旋转强度较大的圆环旋转液体射流,液体黏性的增加,不利于射流的破碎;随着液体黏性的增加,射流的特征频率和最不稳定波数减小.然而,对于旋转强度较小的圆环旋转液体射流,液体黏性的增加,有利于射流的破碎;随着液体黏性的增加,类反对称模式下射流特征频率先减小后增大,类对称模式下射流特征频率增大;随着液体黏性的增加,类反对称模式下射流最不稳定波数先减小后增大,类对称模式下射流最不稳定波数增大.%The effect of liquid viscosity on an annular swirling viscous liquid jet with different swirl strength values is studied with linear instability analysis. The spatial mode instability analysis for para-sinuous mode and para-varicose mode is carried out. An analytical form of dispersion relation is derived, which governs the disturbance growth for an annular swirling viscous liquid sheet with a solid vortex swirl velocity profile subjected to three-dimensional disturbances. The results show that, with higher swirl strength, the increase of viscosity hinders the breakup and makes the domain frequency and domain wave number smaller. However, at low swirl strength, the increase of viscosity speeds up the breakup, makes the domain frequency in the para-sinuous mode first decrease and then increase and makes the domain frequency in the para-varicose mode increase. Furthermore, at low swirl strength, the domain wave number in the para-sinuous mode first decreases and then increases, the domain wave number in the para-varicose mode increases with an increase in liquid viscosity.