图6. $\bar u= 0$时,无量纲增长率$\bar\varGamma _{\rm i}$随无量纲扰动波数$\bar L$的变化
Fig. 6. Dimensionless growth rate $\bar\varGamma _{\rm i}$ as a function of dimensionless perturbation wave number $\bar L$ for $\bar u= 0$ at different $N$