However, as to the para-varicose disturbance, the gas rotation is a negative factor to the instability of symmetric mode, while it is a strong positive factor to the instability of asymmetric mode.

• 对于对称模式，气体旋转运动是低阶模式扰动的促稳因素，然而却是高阶模式扰动的强烈的失稳因素。