电场驱动射流的弯曲失稳分析  

A dynamic analysis for bending instability of electrically driven jet

作　　者：刘岩[1] 张若京[1] 

机构地区：[1]同济大学航空航天与力学学院,上海200092

出　　处：《计算力学学报》2008年第S1期42-47,共6页Chinese Journal of Computational Mechanics

基　　金：国家自然科学基金(10772136);上海市重点学科建设项目(B302)资助项目

摘　　要：本文对电场驱动射流弯曲问题的动力模型作了理论推导和数值分析。在假定射流具有牛顿粘性并作一维流动的基础上,建立了射流运动的控制方程,采用此方程来研究当带电流体穿过电场时受小扰动而产生的失稳现象。将方程无量纲化后,利用简正模态法对控制方程进行了稳定性分析,而后采用伽辽金法求解方程。结果表明,外电场增强、表面电荷量进一步增多(电荷量较大时)、射流轴向流速增大(其值较大时)、射流半径减小以及电荷的分布不均匀性增大,都可以显著增强射流的短波不稳定性;射流偶数阶频率导致了不稳定性,而且阶数越高,不稳定性增长得越快;频率具有虚部,意味着模态中相差的存在;并且射流在短时间内会失去稳定性。A dynamic model for bending process of electrically driven jet has been investigated theoretically and numerically.A continuous,quasi-one-dimensional,dimensionless partial differential governing equation of Newtonian fluid motion has been derived.This equation was used to study the small bending perturbation of a liquid jet when passing through the electric field.With the method of normal modes,the influence of different parameters to stability was discussed.Then,Galerkin method was used to solve the equation.The result shows that strengthening electric field,more surface charge(when its value is large),increasing the axial velocity of jet(when the value is large),shrinking the radius of jet or surface charge becoming more non-uniform will strengthen the short wave instability of the jet;even order should be responsible for the instability and the higher frequency is,the faster unsteady will grow;the frequencies have the image part,which means phase offset exists.The results also show that the jet loses its stability instantly.

关 键 词：电场驱动射流 扰动 弯曲失稳 简正模态法 伽辽金法 

分 类 号：O361.4[理学—流体力学]